I think PoR having Richter and Maria was a bad move. It should've been Eric Lecarde as the secret character. It would've been more fitting, and I'd love to see him do his pole vault move again.
For OoE, it depends. Albus would be a cool character to have as an unlockable, but we don't really know where he stands. If he does prove to be a false villain(and Barlowe is the real culprit), playing through Albus's quest and having the ability to see events unfold through HIS eyes(fighting Shanoa as a boss) would be interesting. I actually would've wanted to see that in Curse of Darkness with Trevor(the boss battles where you encounter Trevor with Hector would be flipped around and you'd be Trevor fighting Hector instead of Trevor fighting Trevor, as well as a additional story about Trevor trying to be an end to the curse himself, with additional dialog between him and Julia, Saint Germain, Zead and Isaac).
As for the reason why the Belmonts can't wield the VK until 1999, it's either a subject that will be covered in OoE or the SotN Radio Drama. Though, seeing how both happen around the same period of time(after SotN, before 1897), I'm thinking there will be some connection(the Radio Drama will lead into the years prior to OoE, set it up as a prelude of sorts).