What is the minimum competency a DM should possess to be considered a good DM?
I've broken the DM skills into seven "professions" and created a poll for each that asks you to vote for the minimum level of competency you believe a DM should have in that profession.
A Dungeon Master must embody a variety of different characters from regal monarchs to leprous beggars. The extent to which a DM can "sell" these characters as believable, the more immersive the roleplaying experience is for the players. How much acting skill should a DM possess?
A campaign world is crafted. Even when a DM runs published adventures, he must weave them into a coherent world. The more plausible this world, the more the players can anticipate events and participate in the world's activities as full partners.
D&D can be seen as a series of encounters. A DM must often run a whole cadre of opponents who must act to counter a strategically advanced party. In this milieu, it is one DM against four or more players. How much skill does a DM need to design and implement a challenging encounter against a team of adventurers.
Sometimes a DM needs to make up a rule on the spot. To do so, they might consider all the traditional hallmarks of game design: elegance, simplicity, balance, and flavor. Some go outside the box and create their own monsters and NPCs. Some DMs go further and design their own spells, skills, and classes for their players to use. Whether you are making an ad hoc ruling, creating house rules, or designing an entire subsystem, the DM is taking on the role of a game designer. but how good a game designer must he be?
Rules disputes happen. It's a fact of life. The DM isn't an advocate for the NPCs -- he is the referee. Sometimes players will have rules disputes amongst themselves, and sometimes a player will interpret on if its powers differently than the DM. Should rules mastery be required of DMs? How about rules lawyering? Should the DM be skilled wnough to exploit loopholes in the rules in the course of encounters, if he so chose, even as players try to exploit such loopholes for their own characters?
DMs present challenges. Sometimes they take the form of combat and sometimes they take the form of ethical decisions. Sometimes, they take the form of puzzles. A puzzle need not be as obvious as sphinx' riddle. It may be more of a logic puzzle, where the players are presented with a variety of competing interests and they must determine who is right and who is wrong. Murder mysteries, political thrillers, social cat-and-mouse, are all types of puzzles that have found a place in D&D at one time or another. How adept must a DM be at crafting intricate plotlines to challenge the players?
Adventuring is all about the story. Whether you run a sandbox campaign or a railroad campaign or something in between, you are still primarily responsible for crafting an engaging story. Whether it's devising interesting NPCs, or fascinating locations, or adventure hooks, a DM writes the material to entertain the players. Must a DM be Shakespeare? J. K. Rowling? A dime-store novel hack?