I don't really have much to say directly about the covers of the Third Edition and v.3.5 Dungeon Masters Guide that I haven't already said about the equivalent Players Handbook covers.
In most respects, I find these two covers just as dreary and uninspiring as I found those of the PHB. I do appreciate what Wizards of the Coast was trying to do with them -- evoke ancient tomes of forgotten lore. However, I simply don't find that particular tack very convincing. At the very least, I think it could have been done better than it was. Chaosium's 20th anniversary edition of Call of Cthulhu, with its faux leather embossed pages and gilded cover, was in my opinion a much better attempt. For that matter, WotC's own v3.5 Special Edition volumes, complete with bookmarks, came closer to what I'd have preferred, albeit unduly expensively.
Given this, I'm instead going to use this entry to comment on an element of the v.3.5 DMG cover and use it as a springboard for a critique of the treatment of D&D in Third Edition generally. But first, the cover:
It might not be clear from the image above, but the globe in the center is in fact a representation of Oerth, the planet on which the World of Greyhawk is set. Now, one could easily take that globe as just a throwaway artistic homage, an "Easter egg" in computer games parlance, intended as a bit of fun for hardcore fans of the game. My first instinct is, of course, to treat as such and appreciate it on that level. After all, the folks at WotC who brought us 3e were unashamed D&D geeks, who often seemed humbled to have been granted stewardship of the first RPG in history. An artistic allusion to Gary Gygax's home campaign would thus be in keeping with such feelings.
Unfortunately, I don't think mere fanboyism is at work here. One of the things we must bear in mind is that 3e made Greyhawk the implied default setting of D&D. The pantheon of the Flanaess was turned into the defaults for the game as a whole. Indeed, a new version of the World of Greyhawk Gazetteer was released for 3e, entitled simply Dungeons & Dragons Gazetteer and whose interior text spoke not of the "World of Greyhawk," but "the D&D setting." This was my first hint that things were amiss in how WotC viewed D&D and treated its history.
From my perspective, the conflation of the idiosyncratic examples from his own campaign that Gary Gygax included in his published works with Dungeons & Dragons itself was the first step along a path that reduced them to intellectual properties. Now, it's true that TSR had trod this path before. I am by no means indicting WotC as singularly culpable in this regard. Nevertheless, I am not happy to see this "tradition" of TSR continued. The vision of OD&D was an expansive one, wherein each referee could create his own campaign world and freely accept or reject whatever elements of the game they wished and yet still remain within the D&D family (provided, of course, that the spirit of the game's rules and literary origins weren't wholly rejected -- there are limits even to a game as open-ended as OD&D). "D&D" was thus a very broad game, individual examples of which had many elements in common but also many that differed. Any examples Gary used from Greyhawk (or Dave from Blackmoor) were just that -- examples. The game was intended to be a generic baseline from which anyone could build their own fantasy campaign.
The publication of AD&D started to change that initial vision. For the first time, we start to see Greyhawk-related names and places enshrined in the rules. These names aren't in any way meant to be definitive, but they're there in a way they weren't in OD&D. Thus, Gary's preferences and predilections enter the canon in a way they hadn't previously. Over time, they acquire the veneer of tradition and so it is that WotC, almost certainly for the most innocent of reasons (at first), takes the next logical step and makes Oerth the default setting of the game, but without acknowledging the setting's history or origins. All "core" products tie into "the D&D setting," which diverges ever more from anything Gary would have created, and they become part of a vast store of IP that WotC sees not as examples or illustrations of how one might use the game to create one's own setting, but as defining characteristics of what D&D is.
The reduction of Mordenkainen or Vecna to elements of the D&D brand reaches its zenith in the publication of Fourth Edition, which cuts the umbilical cord to their origins entirely and treats them as conveniently trademark-able names for selling miniatures and other paraphernalia. Sadly, to many gamers, the fact that 3e or 4e included hallowed names associated with the creator's home campaign is sufficient to argue that these editions are true to the spirit and vision of OD&D. While I shared the outrage of many upon hearing how 4e had jettisoned so many longstanding elements of D&D lore, it was not because I felt that these elements somehow constituted "D&D." To view it thus would be to reduce D&D just as surely to a brand. No, what bothered me was not any specific choice or decision so much as the general belief that D&D's collective history was not merely an impediment to the game's success but also something that could be selectively exploited without context, when convenient. Such corporate ghoulishness is something I cannot tolerate, particularly when it results in products so utterly at variance with the creative corpses being consumed.
D&D may in fact be a brand, but it is not just a brand. It's a fine distinction, I realize, but it's a real one. 3e is where the most pestilential strain of this longstanding rot solidified its hold and the results are clear to see.