A big thanks to TheMormegil, who provided this helpful TL;DR version for those just coming in.
- The lack of flavor in the power system, the inherent modularity of the ToB disciplines and the different feel granted by the combination of disciplines and recovery mechanics make the ToB's manoeuvre system strictly superior to 4E's power system, having virtually all the pros and less cons.- By expanding the concept of disciplines into "Power Schools" you can create a flavorful, extremely modular and easy to balance system for all classes.- Each power source differs from the others for its readying mechanism (changing the way the classes of that power source gain access and refresh their powers). Each class differs from the others by having a unique school that only that class can access, a different set of accessible schools and different class features that alter the way that class is played. The details can be worked out in time and with testing.- The possibility of being able to expand the system easily is one of its major draws, either with new books containing schools, classes, powers, or even through homebrewing (something 4E definitely lacks).- The separation of offensive powers and utility effects grants a nice balance both in and outside of combat, while allowing each class to have its own flavorful options for out-of-combat situations.
One of the big flaws of 4E's power system is the lack of flavor, especially in the higher-level powers, and how it bloats the system with repeat powers. Every martial class with a "+2 to hit, no Str to damage" at-will has to repeat it, every class has a set of encounters that repeat themselves writ stronger every tier. If two classes have a nigh-identical power, it has to be repeated across both classes. This takes up a lot of space and restricts high-level powers from being as grandiose as they should be.
Lately I've found myself looking over my 3.5 books, and in particular at Tome of Battle: The Book of Nine Swords and its various expansion packs on GiantITP and other websites. That book is, in my opinion, superior to the current powers system for three major reasons:
- Flavor: Every school in the book is clearly distinct from every other school, and every technique within that school is distinct from every other technique within that school. While some are stronger versions of weaker maneuvers, the higher-level abilities are also increasingly grandiose in their effects, progressing from slight boosts to normal attacks to magnificent finishing moves that do far more varied things than just add on damage or inflict a one-round penalty. Where a wizard goes from being a lowly apprentice to an archmage, a warblade goes from being a particularly skilled fighter to being superhuman, exactly as high-level play should be. Each maneuver being its own technique and part of a larger library of techniques made them wonderfully fun to roleplay as well.
- Modularity: Each of the Nine Disciplines exists independent of the classes. Classes are defined by their class features and what disciplines they have access to, and each class has at least one signature school that neither of the others gets. This has made the book incredibly popular to expand on, with new classes having large amounts of work already done for them just by virtue of being able to declare an existing discipline as available to them. At least ten new disciplines have been homebrewed just off the top of my head, and all of them had room to distinguish themselves from the others out there. Adding them to play was just a matter of saying "this class can use this discipline".
- Functionality: Maneuvers being broken into stances, boosts, and strikes is like what the Slayer tried to do, only far richer and more rewarding to use. Each maneuver is on its own a perfectly good technique that's very fun to use, and players can construct their own signature move by combining a stance, boost, and strike that they find fit together well, from one or multiple disciplines. Maneuvers are roughly balanced against each other, and the recovery mechanic means players aren't afraid to use them, recover them and use them again. Each class's recovery mechanic and discipline list makes it play differently from the other two, while all three are overall balanced very well against each other. They make fights dynamic and fun.
With that in mind, how can we look at this and create a powers system that captures that same essence, while making classes and power sources distinct from one another? The answer is to think of powers as belonging not to classes, but to schools, libararies of techniques magical or mundane that share a common style or motif. Arcane magic already has seven schools: abjuration, divination, necromancy, evocation, illusion, enchantment, conjuration. The notion of power schools takes this concept and expands it to everything.
Power Schools and Class Structure
Classes under a power schools system consist of a chassis (HP, defenses, skills, proficiencies), class features (at least three-four at 1st level and one every five levels thereafter), a powers known/readied progression, and a list of schools known. Classes are defined largely by what class features they have, the fundamental elements all members of that class share, and the list of schools they know, that is to say what styles of combat they are proficient in. Every core class should have at least one school that no other core class has, but the rest may be shared with other classes, and later classes might get a core class's unique school if it somehow fits them to know as well.
Power Schools and Power Sources
A power source defines two things about a class. The first is its recovery mechanic, the way in which it regains its powers. The second is what its powers are called, and what power schools in general it is likely to have access to.
For instance, martial classes have powers called maneuvers. All martial classes can use a minor action and spend a turn not using any maneuvers besides active stances, though they may still use their basic attack, and at the end of their turn all of their expended maneuvers are refreshed.
Arcane classes have powers called spells, and recover their powers by spending a minor action and then taking no other actions besides moving during their turn. At the end of their turn, they recover all expended spells and can reselect what spells they want to have readied from the list of all spells they know, as they rearrange the magical formulae they can bring to bear.
EDIT: Divine classes have powers called prayers, and their deity plays as much role in deciding what they get as they do. Like other classes, they ready a selection of prayers from the larger list of prayers they know, and at the beginning of an encounter immediately gain three less than this number for use. At the end of each turn, they gain another prayer from the ones they didn't get at the start, and when this pool runs dry they instantly gain a fresh set ready to use again. This gives them a continuous stream of prayers with no need for pause but with less control over what exactly they get than other classes. Class features may allow divine characters to select a certain number of prayers from their list as favored, and these are always granted at the start of an encounter and whenever their prayers would refresh.
Psionic classes have powers called manifestations, and they must shuffle what parts of their mind they bring to bear so as not to overstrain themselves. Once a manifestation is used, the part of their mind associated with that school needs to rest, and they cannot use a manifestation from that school again until they use a power from a different one first.
While power schools all have an associated power source, this does not affect how the power actually works. A martial character who learns a spell through multiclassing still uses their own refresh mechanic for the spell, and a cleric who learns a martial maneuver simply adds it to the list of prayers his deity might grant him.
Contents of a Power School
A power school consists of multiple level-based tiers of techniques, with three-five options per tier, that form a common theme. For instance, the rogue has knowledge of the school Steel Serpent, initially available only to the rogue, that consists of a number of techniques built around stealthy fighting, thrown weapons, and assassination techniques that grow in power, flash and scope in the higher tiers as the rogue progresses from a common thief to a grandmaster to a living legend. When selecting maneuvers known, a rogue can pick any Steel Serpent technique he meets the prerequisites for. New tiers are available every odd-numbered level, with most classes learning a new power known every level and gaining an additional readied power every even-numbered level. Where a low-level Steel Serpent maneuver might be the classic +1d6 sneak attack, an epic-level maneuver allows the rogue to flit around the battlefield like a ghost, appearing from seemingly nowhere and disappearing just as easily, stabbing his opponents with a knife whose swiftly-applied poison will surely cripple them if the blade itself does not do the job. A wizard who focuses his studies upon the Evocation school progresses from simple balls of fire to prismatic storms that change the very shape of the battlefield.
Multiple classes may know a school. For instance, while only rogues know the Steel Serpent school with its great acrobatics and mastery of stealth, and only fighters know the Iron Heart school with its demonstration of pure athletic skill, both classes may practice the Diamond Mind school, which encourages use of battlefield intuition and fighting smarter than the enemy. While only sorcerers may practice the powers of heritage afforded to them by the Dragon's Heart school, their powers over the traditionally arcane are restricted to the bright and flashy Evocation and Illusion schools. While wizards cannot attain the power of dragon blood, their studies afford them mastery of Evocation, Illusion, Conjuration, Necromancy, Divination, Enchantment, and Abjuration, a wider array of schools than any other arcane class and several of which only wizards know. Fighters, similarly, know far more schools than any other martial class, perhaps more than any other class in the game. With the wide array of styles of combat available to them, they can truly be called weaponmasters.
Expanding the Power Schools System
One of the major draws of the power schools system is its ability to expand. Creating a swordmage class does not require creating every power from scratch, instead the swordmage gains a single new school unique to it covering attacks that mix magic and swordplay, then also gains access to a set of schools originally created for the fighter and wizard. While the swordmage does not know all the schools of combat that a fighter does, nor is their mastery of the arcane so varied as a wizard's, they know some of the tactics of both styles as well as a set of maneuvers that are distinctly theirs. This reduces the need to reprint powers and allows classes to share mechanics freely, while making sure each and every class has their own unique style of combat. Multiclassing is as easy as allowing a class to cherry-pick powers from a school outside their forte, though they must ready it as they would any other power.
Power Schools and Utility Effects
Power schools do not generally cover out-of-combat abilities, though cunning players may be able to make creative use of their powers to solve problems in unorthodox ways. Instead, utility effects are provided via class features, and a set of utility powers available depending on a class's power source. These powers are tracked separately from combat powers, and provide for spells, techniques, and other abilities that are not covered by existing skills.
All classes gain a utility power from their power source's list at every odd-numbered level; unlike power schools, every class of a given power source has access to the same list of utility powers. Utility powers should be on par with rituals and martial practices for effects, rather than the existing utility powers, and are oriented around things outside of combat. Players are encouraged to use their utility powers along with their skills to solve puzzles and other non-combat problems.
While the power schools system of class construction takes the best elements of both the 3.5 and 4E systems, it does not cover everything. I have thoughts on how skills should be altered to bring them up to what they should be, but that's a discussion for another time.