I liked the original animated series, but everytime I see new, modern versions of Beyond, I always think it looks quite bad and completely different to the original, not similar at all. Therefore I'm not sure if I would want a Batman Beyond game if it followed that logic.
For example :
Original look :
And here are the "Beyond" outfits for Gotham Knights :
Or here is the Beyond suit in Arkham Knight:
It doesn't look similar at all to me. They always seem to go for either an "organic" suit type of thing, which I don't like, or making the characters look like demons.
I never understood what was up with that, because a lot of people say they love Beyond, but what I see of Beyond never reminds me of Beyond actually, so it's really weird.
Everytime they try to modernize the Beyond look, it just looks ugly to me.
Something like this would be more decent, even if the face is weird:
But if they managed to make it look good, then yes I would be totally up for a Batman Beyond game. The batman atmosphere mixed with a dark slight futuristic tone works really great. I don't know if Batman Beyond is popular enough for that though.