Just wait five years. After all the crappy Trek TV series that are planned are out and negotiations fail with TNG/V/D.S.9. actors, they'll plum the depths of a prequel/sequel series about Gillian before the whales and after the whales. She'll somehow kick people's buts, be woke as fuck, and ultimately be the key to saying the universe.
Send this to CBS/Paramount, I'm sure they'll jump right on this!
I wondered what happened to the actress Catherine Hicks, I was quite taken with her when I saw the film. Checking IMDB I see she kept working, mostly in TV & in some films you've never heard of. It's a tough old business.
Blatant? The way it came up was perfectly natural. Supergirl is pretty damn blatant, even to the point that one of the guys who tries to sexually assault her is wearing the brand on his T-shirt.
As to never seeing her again, it's Star Trek. That happens all the time.
I enjoyed seeing Kirk left to twist in the wind when she takes off at the end. It's funny seeing him not in control. (She probably started boffing McCoy.)