Now that you mention it i've seen that character from old anime and mangas are lacking in almost every hentai game with girl packs like BK; one of the most popular ones is slavemaker (which Goldo took inspiration from for its own creation, BK) and many others similar. Perhaps such characters are not so well known among young '90 devs, who knows? I'm from the 80's and honestly know a little about first Gundam series, so I'm just aware of Sayla's existence but didn't get the inspiration for her pack yet, probably because i'm afraid there are pictures with a too '70s graphics which is not that good compared to modern heroines (but i'm ready to disprove myself on this).
In conclusion, Sayla will be in the poll for her merits ;-) and now I wanna know more about the other chars that you mentioned (we never stop learning...)
every five to ten years there's a newish movie or ova based off the original MSG so Sayla hentai has been present since the early 80's, so you'd be surprised how few dated images you'll find, that and it's tough to find hentai images even from the early 90's (should know use to have a collection, lost it, was never able to recover the images cause better stuff kept coming out so they stopped getting shared.)
Kei and Yuri from dirty pair, there's no real way to explain them it's just something you have to watch for yourself. they'll probably be harder to find images for then Sayla, mostly because there's two variants Dirty Pair & Dirty Pair Flash, tho definitely a franchise that warrants more recognition then it has. (interest really died out on them sadly even tho they check most of the boxes for popularity.)
as far bubble gum crisis goes chances of you successfully pulling off anything with even one of the girls from it is slim even tho if you'd watch the series, you'd think otherwise.
the only I thought of these three is because they've all impacted either mainstream culture or our Niche side of things at one point, I'll probably think of something to replace bubblegum crisis cause really it's an impossible task.
lets see what could I think of that had a fundamental effect your choice, any of the girls from Ranma 1/2 or Lum-Chan from Urusei Yatsura, since both had major impacts on animation and hentai & are much easier to work with.
(yeah serious Game, Comic, and anime enjoyer here :/ most of what I watch now is older then me.)
