If it were to happen, here's what's I would want for it.

1.) A blend of 3DCG and 2D Animation. 2.) Adaptation of the entire Manga series, even showing stuff that's not in the movie and OVA like (Spoilers for the manga) Alita and Hugo fighting a werewolf, Hugo's backstory, etc.) 3.) Some of the movie's cast to reprise their roles for voices. 4.) Retaining the R-Rated content from the manga (albeit being censored for TV if it comes to TV which may not happen) 5.) Being a 24- 26 Episode series that covers the entire would be great but I think that it may go for a 6-10 episode structure to contain multiple seasons (if it becomes successful)

But...this is just wishful thinking.