Until WotC starts putting out base classes more powerful than the core's Big Three (druid, cleric & wizard), I'm not going to worry too much about power creep. As far as I can see, the only power creep in the Complete series comes from more options (which, ironically, helps the Big Three more than anyone else) and a handful of poorly designed prestige classes, like the Hulking Hurler.
What I find funny and/or sad is that the dual bugaboos that WotC has backed off from (beyond 20th level and campaign settings) are the two areas with the most room for expansion. If they want to keep pumping out books, which they must to stay afloat, they'll eventually run out of things to say about Core D&D. They'd never run out of things to say about Spelljammer; heck, they've never run out of things to say about the Realms, and probably won't about the vast and unexplored lands of Eberron. And having, say, five books with 20 unique levels each (rather than theoretically infinite levels, ala the original ELH), would quintuple the amount of material they have room for.
Is there a market for campaigns and what is presently defined as "Epic"? Maybe not. But if not, WotC is going to have a very hard time finding new material to release outside the Eberron and perhaps Realms lines. Especially material targeted at players rather than GMs. Draconomicon and its kin are almost exclusively GM-focused, and even the regional books offer less to players than a class or race book.
Overall, I don't think WotC has any of the same problems TSR did with 2e, nor, for that matter, any of the same strengths. I also think the latter are more than most people give them credit for. TSR's problems went a lot deeper than its business model or the (severe) problems with AD&D 2e.