I hope that if a sequel is made they dont make the setting in the future like the ending suggests, we have almost a 1000 years from each point were a new canon can be introduced, maybe introduce some of the old characters(but not exagerated like what they did with DmC) and stories reimagined, like Leon, Trevor, Sypha, Grant, Simon, Richter, Alucard, Maria, etc, also, make the Belmont/Dracula dynamic more fleshed out instead of a he wakes up lets kill him, also make the battle cross(Vampire Killer)more important, it would be a waste not to take advantage of that.
Also, some of the old subweapons could be reintroduced like the cross bommerang, or the watch which could only be used with magic expending it faster than normal to prevent abuse and having different properties with the kind of magic its used with and maybe using it on the platforming side of the game, introduce classic monsters like mummies, frankenstein monster or frankenstein himself, gorgons, mermen, ghost dancers, or bosses, like succubus, Medusa, Slogra and Gaibon or Legion(legion in glorious LoS 3d would be epic with all the bodys as the outer shell falling of as we hit it and stuff).