MetroidVania with a 2D open world aproach kind of like in Simon's Quest, but every mansion containing several different areas, all with its own music, composed by Michiru Yamane, Yasuhiro Ichihashi, Sotaro Toshima and Yuzo Koshiro, all with map percentage, with items, equipment, levels up and all kind of stuff, like side quests, rescuing maidens like in Rondo of Blood, and characters designed by whoever's been responsible of stuff like Sora No Otoshimono, Rosario To Vampire and High School DxD.
Graphics would be with sprites, following the atmosphere, if possible, of Symphony of the Night meets Dracula's Shadow (an italian fan game).
The difficulty would be something at the level of, say, OoE (CotM is just too much), but with the option of grinding to gain levels, so you can level your way through the game if your skills or patience are not enough.
The main character would be someone like Charlotte (but a new character), focused in spells and magic, with a partner like Jonathan, but more manly, and extra modes would include all kind of new characters, each with its own gameplay.
That pair of characters is the ideal pair of lead characters a game can have. A handsome man (not a teen, a grown up man, like, say, Brad Pitt in Troy) and a gothic loli character.
The story would be tragic and the game, despite having multiple endings, wouldn't have a happy one as the definitive ending.
It would be for PS4 and PC, because it's been enough time since the last time we had a 2D retail for a home console.
The pre-order would include a soundtrack, an artbook and an autographed giant poster with all historical CV artists signatures (not massive prints, real signatures, signed one by one).
Since the costs of production would be so high that no possible sales would save the economy of the project, the game would mean the end of Konami and Castlevania would become the new Megaman.
Yeah, even when I'm dreaming I'm negative...