"What's the Dungeon Master's real role?"
Dosen't the answer to this vary from group to group and style to style?
For my part - as a GM, my most important jobs are (i) to set up the situations that confront the PCs (which means authority over situation and over a good chunk of backstory), and (ii) to play my part in the action resolution mechanics - which means (in 4e) choosing actions for monsters and NPCs, keeping up the pressure in skill challenges, and adjudicating page 42.
As I read it, Monte's column is mostly about (ii). My personal preference in relation to (ii) is for a game that reduces the need for the GM to invent new resolution mechanics, and that presents robust mechanical guidelines (in 4e, DCs, damage expressions etc) that permit adjudication to be done in a maximally thematic and minimially adversarial/"mother may I" style.
An ounce of flavor text is often worth a pound of rules crunch.
Consider the venerable fireball.
<snip>
you can say, "This spell creates a tiny glowing bead that streaks to its destination and detonates in a 20-foot-radius burst of flame."
This does not state that you can use the spell to set a barn full of hay on fire, or to create a momentary burst of illumination, or to signal someone from miles away if you cast it straight up into a night sky. Yet all of these are implied by the flavor text. A player who reads that text does not have to ask the DM if she can do these things; it's clear that she can, even though no rule says so.
I quite like the way 4e handles this - that is, not via flavour text, but via keywords. Fireball has the
fire keyword, and hence does damage by conjuring flames. From this the ability to set fire to hay, to act as a flare, etc can all be inferred.
Another example that came up in my game on the weekend involved the
fear keyword. The Enigma of Vecna has a "horrific transformation" power which causes an attack vs will dealing psychic damage and pushing the target away. The fact that the power has the fear keyword indicates that the "push" is, in fact, the victim fleeing from fear. (Some wights have a similar ability.)
The item damage rules in 3e (
and 4e <- DDI Link) fall mostly under the "too detailed to be effective" bucket of rules.
Of course, the crux of the matter is, "if I need them."
The role of keywords, of anchoring the mechanics and the fiction, is made clear in the DMG's discussion of attacking objects. As you say, however, this is a rather peripheral component of the rules. I think the importance of keywords is something that would be better stated as key principle of action resolution adjudication.
The problem is compounded by the fact that, in the discussion of keywords in the power rules (PHB, Rules Compendium, etc) they are discussed
only in terms of their interaction with other mechanical elements of the game, rather than also in terms of the role in linking mechanics and fiction.
WotC D&D, but especially 4E (which I enjoy, btw), is designed in such a way that there are so many secondary and tertiary elements that the player is further removed from their character, and ends up running their character like a piece on a board game or a video game avatar (at least in combat, which is why some have noted that 4E is like two games in one: the actual role-playing game that takes place outside of combat, and combat that is essentially a miniature skirmish game).
The experience you describe here may be common - I don't know - but it is not universal - because I don't share it.
This relates to the role of keywords, and also to page 42. 4e combat in fact (in my experience) makes the fiction, and fictional positioning, pretty important, but the presentation of the rules tends not to draw attention to this.
One simple example: suppose a combat involves a stream or pond which is difficult or perhaps hindering terrain. How can the PCs interact with this? One way is to use Icy Terrain - a 1st level wizard encounter power with the
cold keyword - to freeze the water, turning deep water (hindering terrain) into difficult terrain, perhaps, or at least less hindering (Acro checks to maintain balance rather than Ath checks to swim); or turning a shallow puddle that is difficult terrain into an ice slick that is modestly hindering terrain (Acro check to maintain balance).
If the difficult or hindering terrain on the battlemap was instead a boulderfield, or a mass of tangled vines, then Icy Terrain would interact with it completely differently.
Rather than reinventing the basic action resolution mechanics, I think WotC should think hard about how they right their guidelines for GMs and players. If you spend pages talking about the minutiae of adjudicating cover and line of sight, but say nothing about how keywords anchor the mechanics in the fiction, and in turn therefore provide conduits from the fiction to the mechanics - instead talking only about the mechanics-to-mechanics role of keywords - is it any wonder that some people mistake your RPG for a skirmish boardgame?