As for the original discussion, there will be overload and bloat somewhere; that's just part of developing and sustaining an rpg. The only real question is where, how quickly, and can they keep it contained enough so as not to become the defining feature of yet another of their rpg systems.
As for the discussion that it has evolved into, D&D could potentially develop into something greater than the rpg, but I have a really hard time seeing it with this company. Their novel line, which is the only current major line outside the rpgs as far as the general public is really concerned, still relies almost entirely on a 2E author and a 2e character, both of which where basically inherited by WotC when they first purchased the IP; also, most D&D novels aren't really sold as D&D novels, but rather as Forgotten Realm novels or Drizzt novels, weakening any recognizable ties to the overall D&D brand. Computer games have been a mixed game at best, managing to sustain the interest of the established fanbase, but not really doing a lot to reach out to the general public. The boardgames are successful, as one would expect from a Hasbro supported company, but board games are themselves a pretty niche product that aren't going to really strengthen the brand as a whole sufficiently to take weight off of any other part of the brand. The movies have been a nonstarter for over two decades now. On top of that, they aren't even as sure bet anymore in the rpg market after the difficulties they had with the launch and first several years of 4E; Next's launch will certainly be successful, but it's sustainability is still very much up in the air. The problem that WotC has with the D&D brand is that just because the pieces are there, there isn't much interest in the general public, or for that matter, in any of the individual niche markets the different products inhabit, to really tie them together into a singular brand recognition, due largely to the fact that none of them are really are that particularly relevant to each other or to anything outside of their individual markets. If, and this is a very big if, they can manage to get the public to see all of the parts as a single entity, they could do very well, but they have a lot of challenges to get to that point.
First, they need a single focal point for shaping and guiding the game and the brand; one of PF's strengths is that even if the core books are technically separate from Golarion, Golarion is still there to provide a solid and consistent background. Also, it is able to provide a consistent and steady background for the novels and adventure paths that are really at the heart of Paizo's business model. Without a similar consistent backdrop to develop official product around, including the core rules to a certain extent, it will be very hard to develop any kind of overall identity between the different products. Iron Man seems to be a popular comparison here as well, and it's worth noting that while details about Tony Stark, his origins, and his capabilities have changed over the years, the core superhero is still recognizable; same with all the other superheroes for the most part. From what I have seen, they seem to be trying very hard to setting up Next to be the unifying force, but given their mixed record of success in pulling together the different parts of the brand thus far, despite numerous attempts by numerous teams of people, and there is plenty of room for skepticism.
Second, after they have achieved that first concern, and they must overcome that first concern for the second to have fertile ground to work with, they need a breakout movie or a breakout video game as a showcase for the general public. If they have not yet succeeded in overcoming the first concern, than the second has no chance of success because without that unity of brand recognition, the general public will see what it has seen for so long now, an interesting enough brand that has some name value and a little bit of nostalgia, but no real clear message of what the brand is. A strong vehicle is great, but it's got to have a strong message and brand to carry for it to have any effect, which is why the few successes that WotC has had as been limited to niche markets and/or short term bursts of success.
Someone's characterization of D&D as a mishmash of Tolkien and a few other sources may be a bit harsh, but it's not entirely untruthful, although now, it's more a mishmash of tabletop rules, a handful of worlds that are recognizable to varying degrees to different markets, and a handful of characters that do a really good job of representing themselves, but not really the brand as a whole. If Hasbro and WotC put their head together and figure out how to get all the moving parts of the brand in the same direction at the same time, they have a lot of potential on their hands. My biggest concern is that they basically have to do it with Forgotten Realms, since there is practically no way to get the novels to budge to another world without losing a lot of their readership, and to say that Forgotten Realms since 2E has been a bit unstable in it's development and consistent execution of story lines is a vast understatement. More notably to me, even at it's most stable, it's a very polarizing world. Golarion or Greyhawk are not exactly beloved by everyone that uses them, but equally very few people despise them and refuse to learn anything about them; Forgotten Realms, on the other hand, has had a tendency to focus very sharply on a handful of elements that stir up as much dislike as favor, while the rest of the world remains frustratingly blurry except when it's spelled out to the smallest of details.
So, for me at least, they are already starting with one strike against them because Forgotten Realms has not demonstrated itself to be of much good for anything save Forgotten Realms; the overall D&D brand has yet to see a lot of benefit from it. Throw in another strike that they can't seem to sustain a single management team long enough to both lay the necessary groundwork for a successful implementation and keep them around to actually implement it rather than relying on people not steeped in that particular vision, and you are looking at a second strike. I have no doubt that they will manage to avoid a flat-out third strike, but the question is do they finally manage to knock it out of the park or do they just manage another weak hit that keeps them going, and if it's the latter, how weak of a hit will WotC and Hasbro tolerate and deem strong enough to keep the brand going to try again. A lot is banking on them getting movie rights back and making a strong movie based in whatever core world they decide to make the primary focus of what they need to be a long term success of Next; that's a lot of moving parts for a company that has not shown a history of being able to manage a lot of moving parts. Is it possible? Sure, but it's far from a sure bet.
