Just because a game uses a 3D GRAPHICS ENGINE, does not mean it has 3D Gameplay.
Know that graphic designers do not do the same job as those that program the game play system and mechanics.
Case in point, strip away all of the graphics from Street Fighter IV, and all that is left is 2D hitboxes.
Just the same if one was to remove all the graphics from HDR and all that remains is again 2D hitboxes.
You can make proper Darkstalkers game using the engine that Street Fighter IV uses, the only adjustments that would be required are the game’s speed.
Darkstalkers overall was somewhat more faster paced then Street Fighter.
What separates Street Fighter IV from games like Tekken, Virtua Fighter, or even Soul Calibur which are true 3D Fighters is that at it’s very core the SFIV gameplay engine still uses 2D hitboxes (you could keep Street Fighter IV identical as it is, remove everything and simply leave dots to represent the characters and one would not be able to tell the difference)
Minding that the game plays like Darkstalkers, keeps essence of what makes it Darkstalkers game, the mechanics of a Darkstalkers game, then the game could essentially be a Darkstalkers title regardless how it’s presented on a visual level.
Minding they keep the game to using 2D hitboxes for attacks, to retain the core of what makes a 2D fighting game (controlling space), and Darkstalkers could be presented in a way that casual players that have never even heard of the series could also be interested in picking it up.
Remember to Capcom it’s all about the sales, they are a business. The more people that buy this game, the more they consider it a success, this would just be another nudge to convince Ono’s superiors that the Fighting Game genre is capable enough to contend with other mainstream games. The expansion of the community and bringing potentially even more fighting games introduced to the market is a good thing.
And even if a NEW Darkstalkers game (NEW as in all entirely new, and not simply a remake, rehash, or re-release of an old game) is what stems from his efforts, then that makes it all the more worthwhile.