Bottom line:
They must bring back old fan favorites, meaning, characters.
There is zero reason why they can't bring back those fan favorites.
We all know Jill and Claire can be brought back as playable characters, but what about bringing back Ada as a playable character?
Third person, CCTV camera angles, pre-rendered backgrounds, pretty graphics. Put me back in a big, plush mansion, clock tower, castle, palace, puzzles to solve. I loved Code Veronica because you run around in a beautiful palace and it's partially destroyed and burning with zombies roaming around. It's the beautiful and the hideous coming together to make you panic, because you can see how the evil and corrupted is slowly taking over and you have to find a way to survive. Back to basics and keep it simple.
The rest should be pretty academic.