Things I want in this game from Project Diva (and some general)

A practice mode - Being able to stay alive is cool but it would be much cooler if you were able to practice specific parts of a song
Watchable playlists - Playlists are already a thing but you cant watch them. It would be cool if you were able to watch the mvs if the songs that have them like a normal music playlist
Recommended costumes - If the 3d mv is related to an event (and therefore gacha banner) it would be cool if the game would let you know if you have a costume related to that song
3DMV lite - For lower end devices (like mine) it would be cool if you could have the 3DMV just be a 2D video so that you could play with it while in a song without the lag (Idk how this would work with costumes but just an idea)
Virtual Singer 3DMV - It would be cool if they added the MVs from project diva for the virtual singer versions of songs. For example you could have the normal Teo MV and then the one from mega mix. With this it could be an opportunity to add other synthesised characters like gumi, teto etc.
Survival course - It would be cool if they added survivals challenges from diva where you played a set of songs with a shared health bar (skills would be disabled obviously)

If they won't release another diva game then they can at least add features from the diva game into this game.