it has hand-drawn animation for the characters and painted backgrounds for the stages, on par with Skullgirls and Cuphead, and retains the gothic horror Tex Avery anime aesthetic the older games had
it has every veteran back (there's only 18 of them)
they make at least...idk four? new characters that would fit right in with the old ones, and all still based on horror stuff (some ideas I had: witch, Invisible Man, dream weaver [basically Freddy Krueger, or Death 13 from Jojo], blob monster, calaca, big buff slasher villain-type guy, dullahan). Generally speaking I would want at least one newcomer that isn't a cute/sexy girl though obviously those are fine I just think that's not all the games are.
the gameplay is mostly the same as Vampire Savior's but with quality of life fixes, bug fixes, a more forgiving input system similar to those found in more modern Capcom fighting games, etc. - though any new ideas they have for mechanics (particularly defensive ones) are appreciated if done right, it is a very different beast from SF and Marvel, and I think preserving that is a key to the appeal
for other content, it has perfect online (including cross platform) and a perfect training mode
This game would take nine years to make and if advertised relentlessly might sell 500k.