I would think that payment is an issue. I mean, would you REALLY draw more sprites when you arne't paid to? If you do, then you're encouraging them to not pay you to do other work, then you end up being the one who did loads of work for no payment.
Ask yourself this question then but first pretend you are a game designer or whatever.
Would you get paid more for making fully redesigned 3D models program them then implement them into a game thats on a next gen system (or current gen whatever) or would you get paid more for drawing some new sprites to the quality of the DS castlevanias?
And yes that was a rhetorical question cause we both already know the answer.
I think the answer is very clear here. They had the resources to create a new 3D fighting game with brand new 3D models, that mind you interacted in their own way without copying any of each others move sets. Even Simon and Trevor played very different for being very similar characters. So therefore they had the resources, time,
money, and everything they needed to implement characters from other Castlevania games that IGA had nothing to do with. But thats not the point, the point is this. IGAs team has shown they have some potential to do some pretty cool things yet they miss the mark thus disappointing many of their own fans. Much like how many musicians or actors that are consider washed up do. They show that old familiar spark but they still miss the mark for whatever reason. Hes already got up on stage and asked fans to support this game which personally i really felt sorry for him for doing. Personally my own personal agenda against IGA is this, I just want the guy to do something great because obviously he has the potential to do so, yet he misses the mark and every game he has come out with here lately has been wasted potential. Take Curse of Darkness he had an opportunity to bring back soem old faces and throw in some really cool shit. We've discussed this many times of how people wouldve liked to seen Sypha pregnant or tugging a long a little Belmont with a make shift whip, or as you entered Cordova town to help assist Grant in fending off the monsters as he was trying to help rebuild Transylvania, or as you entered one of the towers you stumble across Alucard's resting place much like how Zack stumbled across Vincent in Crisis Core. He could've done us all a favor and created another 3D castlevania game where you play as Dracula going up against Mathias and thus retconning that whole Mathias is Dracula non-sense.