I do blame HD gaming. Costs to make games are more expensive now than ever, so developers are trying to earn back their costs(and then some) by catering to the popular trend.
That may be true, but we've seen some outstanding hardcore, unconventional titles transcend this issue in the current generation. Demon's Souls is the prime example, flourishing in the West through word-of-mouth despite its relative lack of Sony [Japan] support and zero marketing. Atlus itself has some strong examples in its Persona series, which always make the most of a small budget and often manage to deliver better gameplay than the multi-million-dollar Final Fantasy entries of late. Digital distribution through Steam, PSN, and XBL has re-opened the doors for smaller studios and greatly revitalized retro gaming. And we've seen a revival of 2D fighters and side-scrolling platformers that would suggest that many gamers still value gameplay over cinematic presentation.
Perhaps we need another bold SotN-type scenario to revive Castlevania properly. What I mean by that is this... SotN came out at a time when 3D seemed practically mandatory for 32-bit disc-based platforms, boasted some decidely old-school mechanics, yet made the most of SS/PSX technology by dropping in pieces of 3D, beautifully smooth sprite work, and deep layers of parallax.
If Konami bravely crafted an HD 2.5D Castlevania for consoles, using traditional side-scrolling gameplay mixed with 3D assets, this would make several things possible:
1) Development costs would be drastically lower than that of a fully 3D game.
2) Hardcore old-school fans would appreciate the construct of traditional Metroidvania titles, but mainstream gamers could enjoy HoD-esque cooperative connectivity and the cinematic presentation that 3D assets would allow.
3) 3D assets would also allow complete visual customization of characters, perhaps even full character creation.
4) Ecclesia's world map system could be evolved and incorporated to lend more non-linear exploration to the game, which has almost become a prerequisite for games with RPG elements.
5) Side-scrolling games often allow for greater detail in level design because they don't suffer the spacial issues and technical limitations of full-3D with a roaming/controllable camera, thus allowing the visual style to be more unique, perhaps even moving closer to Ayami Kojima's artwork with the right filters/shaders.
There are other advantages, as well, but such a game could be released on a limited edition retail basis with a stronger focus on digital distribution [to bloat profits considerably, with less overhead to boot]. Slightly lower-res handheld editions would also be possible, so innovations like cross-platform play might be possible. It would be a gamble, for sure, but would it really be more risky than the entries we've seen in the last decade? I doubt it.