Walk: Phrases like "If you walk at least 10 feet and then make a long jump..." bring silly images to mind, like mighty heroes speed-walking toward a dragon. I never thought of the default move-speed in D&D to represent walking but rather something more brisk. The term for moving one's movement speed should probably change:
Walk=>Hustle and Hustle=>Sprint (or Hustle=>Run)?
Jump: I am glad the randomness of jump height/length from 3E is gone. I still think it would be great if there were room for Strength checks in some way.
Climb/Swim/Crawl: I love the simplicity of making these movement modes simply act like difficult terrain. Maybe it's too generous, but I think simplicity trumps realism in these cases.
Anyway, it should be explicitly stated that an unsuccessful Strength check for climbing or swimming results in no movement (or worse: falling/drowning!).
Stand up from prone / Getting knocked down or tripped: Standing up from prone only costs 5 feet of movement. That saps only 1/5th or 1/6th of a PC's total movement pool. In 3E, standing up took an entire move action and provoked opportunity attacks. Falling down sucked. However, back then, a trip action was a big deal: you usually needed to be a monk, or a big monster, or have a special weapon and feats to do it reliably. Now in 5e, Knock Down is a a mere STR vs STR/DEX contest, and Trip is a maneuver that always works for the cost of 1 martial damage die.
I like how it's easier to trip now, but what does it even end up doing? Basically, you sap 5 feet of movement from the enemy's next turn, which he probably wasn't going to use anyway while locked in the combat hug. However, all of your friends who act before the enemy will gain advantage when attacking the prone enemy. Ooo! (Good time to remind your rogue buddy about readying actions). Only by having friends ready to lay the beat-down does a trip ever make tactical sense. Seemed odd to me, but interesting.
My feelings are divided. I like that it's way more fair to both sides now, easier to arbitrate, and definitely not game-breaking anymore. However, three problems, some of which have existed between D&D editions:
1. No reason to remain prone; when would you ever choose to suffer -2 to attacks of the prone condition over simply standing back up? In 3E, you might remain prone to avoid an opportunity attack. In 5E, you will pop back up like an inflateable clown with next to no effort.
2. Imagine a character intending to walk 30 feet but hits a trip-wire trap that knocks him prone. He can now get up for only 5 ft and still make it 25 ft. Barely phased him. Standing up ought to consume greater effort and act more like an impediment than it is. (Should it cost 10 feet? 15 feet? Half your movement?)
3. How many movies can you count where there is a knocked-down-followed-by-frantic-crawling-away scene? I'd like to imagine a situation where a hero might get knocked down, then choose to crawl under the tables to dodge opportunity attacks instead of jumping back to his feet immediately. (What if crawling in certain areas could grant cover versus opportunity attacks? Or if crawling never provoked OAs?)
Disarm / picking up an item: Very simply, if I am disarmed, and the item drops to my feet, the rules seem to state that it takes absolutely no movement to pick it up again. What purpose does disarming serve? Shouldn't it tie up an opponent's attack, instill a penalty, force him to resort to a backup weapon, or something like that?
Breaking up a Move: Whoaaaa... This is new to D&D. I could see this used as a poor man's Spring Attack (provoking an OA against an artful dodger rogue or something), but otherwise it surprisingly doesn't change things up too much. This also frees up the move/swift/free action paradigm to a movement pool model. I think I like it.
Opportunity Attacks / Ranged Attacks in Melee / Disengage: Only moving out of reach triggers opportunity attacks. Moving within reach does not (and should be explicitly stated for clarity). This means if I'm standing next to an ogre, I can circle-strafe 6 squares around him without issue. This is odd but maybe 5E heroes are just quicker on their feet.
Of course, since there's no flanking rule (yet?), getting circle-strafed is not much of a problem for the ogre. He can just circle-strafe you right back. If the ogre moved up on the mage or ranger, they're also relatively safe because opportunity attacks are not provoked by magic / ranged attacks. They can just keep plunking away at him, point-blank.
1. No reason ever to whip out the backup weapon. I would like to see a reason for the mage to clunk an orc on the head with his staff, or for the ranger to drop his bow and grab his swords. If the party fighter can cover you and threaten your foe, it should be a smart tactical choice to Disengage (forcing the enemy to either suck up the fighter's opportunity attack to pursue you or also choose to disengage, thus wasting his action).
2. It is paradoxically easier to move around a dragon's reach than an orc's reach (could be wrong; haven't read special big monster abilities yet). Same goes for players with reach weapons (though Warding Polearm addresses part of my issue).
Shift: Without the Shift feat, everyone still has some movement versatility, so long as they stay locked in the combat hug. With the feat, you can finally withdraw from the sticky combat hug embrace without wasting an action. Keep in mind, this will only work to your advantage if you have a tanky ally who doesn't mind staying locked in the combat hug and who can threaten the enemy with an opportunity attack if the enemy keeps chasing you. Without that ally, Shift is worthless, since the enemy can easily close in on you and attack. Since there is no penalty from point-blank ranged/magic attacks, might as well stay still.
I would like Shift to lose its feat status and return to being a mere mode of movement (3E/4E style). Ranged/magic attacks should also provoke opportunity attacks. This forces the ranged/magic user to keep backing up until he hits a wall or gets trapped by multiple enemies. What should he do then? Cast a melee touch spell, bring backup weapons, call for help, blow himself up with a fireball, or try not to get caught out in the first place!
Indeed, the melee dude still retains a tactical advantage against the ranged/magic user, because the aggressive melee dude can now guide the other's shifts. This can be accomplished by following the ranged/magic user, then moving around him and standing in the opposite direction of where he intends you to shift next turn. (In 3E/4E, the retreating player mostly controls the flow of movement. In this example, the aggressive unit maintains control by "herding" the retreating player in the desired direction). Imagine the tension of being backed against the edge of a cliff, then not knowing whether to risk the opportunity attack or to try plan B, whatever that may be.
By the playtest packet (where Shift is a feat), the combat hug might never move anywhere if one of the combatants decides to stand still. One enemy can lock a player down to the 8 squares surrounding the enemy. Two enemies standing diagonally a player can effectively lock a player down to one spot. Either way, the locus of the fight remains boringly static.
If there has to be a feat, make it Improved Shift, which would allow for 10-ft shifts or something like that.
Charge: The Charge feat, which allows you to move up to your speed and make an attack in one action, should come with a note: this is in addition to your regular speed. Essentially, Charge lets you move 60 feet and make an attack instead of 30 feet and attack, or 60 feet and stand there staring at the enemy (hustle). (That final 30 feet of the charge must be in a straight line). This is so weird and awkward ability, I don't know what to think.
Problems: Shouldn't everyone, even the lowliest peasant, know how to charge? How do we eliminate the awkward situation where both groups are 40 feet away from each other and neither wants to move in closer?
Move+Attack vs. Charge: This is an interesting distinction I didn't realize until I started thinking about the numbers: We're in a fight, and I disengage, hoping to get as far away as possible. Both of us have a move speed of 30 feet. The terrain is flat and stretches on forever. If I disengage, I move 10 feet, then I take my regular 30 feet move to get 40 feet away from you. You try to close the gap, but you're 10 feet short, so you have to Hustle to get to me. No attacks. I disengage again, move 40 feet... and so on, I kite you forever, making CON checks until we both pass out.
Charge should fix that situation: I move back 40 feet, and you charge me. Great! However, even if I'm faster than you (up to 50 ft move speed), you can always keep charging me and catching up. Should I really need a feat to catch up on an open plain?
If everyone can charge, then the problem goes away. The only way I should be able to escape (and thus trigger a chase contest) is by ducking behind terrain and preventing your charge, as it should be.
If there has to be a feat, make it Improved Charge, which eliminates allows you to avoid OAs during a charge, increases attack bonus, increases damage, allows curvy movement, or something like that. Let's wait and see what the Barbarian will bring to the table first.
Moving a grapple creature: Basically difficult terrain? Love it!
In closing, I like the tactical variety of grid combat but I also appreciate simplicity. I am concerned that it's too easy to stand up from a Trip, while Disarming an opponent is worthless. I find it extremely odd that Shift and Charge have to be feats. A lot of these actions didn't make immediate sense to me, or work counter-intuitively, but that's not a bad thing so long as the ability/feat description is clear how it works. If changes like I suggest aren't made at some point in the future, I would still love to see them as optional, modular parts.