As far as the DM not being able to say no or it being a matter of power, I disagree. If the players are unwilling to deal with reasonable guidelines and world builds, then the DM isn't doing themselves or the players any favors by letting them run wild.
Again, this seems to assume something about the GM/player relationship ("letting them run wild") which is not true in all groups.
Eric Wiener/Paradigm said something over on the Witch Hunter thread that really struck home with me and seems to illustrate what I am trying to say with regards to this
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D&D, be it 3E, 4E, OD&D, or 12E, is certainly playable out of the box. Does whichever edition address everthing for everyone? Quite possibly not; however that doesn't make the edition not playable by any stretch.
I saw that post. I don't think it applies to high-level 3E. Nor, I suspect, to 1st ed AD&D. It is certainly true of Moldvay/Cook D&D. (I know, I played it out of the box. I also had a lot of fun with AD&D, but I don't think I could have got a game out of those books if I didn't already know Basci and Expert D&D.)
In part, I guess it depends on what you mean by "playable". In a very literal sense 3E has rules that will allow an RPG to be played. But compared to the play experience that other games offer, it seems not to deliver everything that might be expected from an RPG play experience. On the thread debating the Fly spell in 3E and 4e, someone (AllisterH?) made the point that 3E suffered from just cutting and pasting the old AD&D spells into an otherwise very revamped ruleset, without really taking account of how that might affect gameplay. I feel that that is true - that 3E is, to an extent, caught between two stools (AD&D on the one hand, and more contemporary RPGing on the other). 4e has definitely chosen which stool to be on, and is very obviously (to me, at least) AD&D no more.
(A further complexity is that, unlike many other RPGs, D&D is expected to be (nearly) all things to (nearly) all people, so that what is even meant by "playing D&D" can vary wildly from group to group.)
The edition-wars ban makes me hesitant to say too much about (what are, in my opinion) 3E's flaws. But when I compare it to other games - some from a much earlier period, like RQ or RM - it doesn't necessarily measure up all that strongly.
The four posters on these board who seem (to me, at least) to best capture the limitations of 3E as an RPG are Hussar, Doug McCrae, Mustrum Ridcully and Ian Argent. Those limitations are a result of (among other things) the extremely rapid scaling of numerical bonuses (and hence the need for a comparably rapid scaling of level-appropriate target numbers), the divergence of those bonuses from PC to PC, the rapid growth in hit points and damage potential, and the divergence of those numbers from PC to PC. A consequence is these limitations is the difficulty of designing satisfactory encounters for mid-to-high level play. And that is a mechanical thing, not a playstyle thing.
The way that bonuses are developed and deployed in games like RQ or RM means that this scaling issue does not become a problem in the same way. And in RM, at least, it is possible to design interesting encounters using a wide range of creatures. In particular, the mere fact that the PCs have significantly higher skill numbers than their enemies doesn't mean that a combat becomes uninteresting to play out. There are still meaningful decisions for the players to make, and meaningful consequence resulting from those choices.
There are other issues also that I personally have with 3E - eg its emphasis on encounter grinding as the main focus of play, which is espcially apparent in WoTC modules - but I think my taste in adventures is probably a little different from the norm for ENworld. This feature of 3E adventures also has a mechanical cause - namely, the reward (ie XP and treasure mechanics) - but I'm probably in a minority in identifying those mechanics as flawed.