I just wanna say that Donkey Kong Country Returns is a damn awesome game, and I'd love a Castlevania game to be in that vein.  You know, revamped.
Just as long as Castlevania doesn't end up looking too cartoony in the polygons. I guess Drac X Chronicles was a good starting experiment, though. 
...I think CV-V would be possible considering what was done with Rebirth. I mean, Rebirth was, in many ways, a low-budget, slapdash game, but it had the core that captured Classicvania (dare I say, CV itself) better than anything I've played in years. If there was any kind of budget, with the right mindset, I think a new 2D Classicvania could be amazing. But yeah, 25th Anniversary won't go anywhere big with what's going on at Konami. ...The long-lasting Contra's big anniversary was Contra 4--but that was an awesome game, despite the small scale.
Keep the saga in the "niche" and it will ever be niche
Yes, but if not being niche means losing the Castlevania feel, I don't know if there's a point. Castlevania's in a tricky spot. It put a lot of its gambling chips on LoS, and now it has even more identities to balance. Ultimately, I think Castlevania has to boldly be what it 
is (Gothic-Hollywood monster slaying with the whip, man vs. Dracula, without high-fantasy pretenses and without Shakespeare) if it wants to get noticed again in a big way. It may be too late. Instead of consolidating, LoS tried redefining, which just made it look like a slapdash of a handful of other titles by and large, IMO. Castlevania won't break through until it asserts itself.