Because all of the cool kids are doing it, I'm now thinking of ALL OF THE PACIFIC RIM FUSION AUs.
It's not as simple as throwing pairings into the Jaeger, because it's not just about their romantic chemistry, it's about their ability to work together as partners to kick ass.
That's why as much as good as Kameshige are together, I think Tanashige has the edge as co-pilots. Of course, we could go the Chinese-triplets route and just have a Rookies tri-prilot Jaeger, WHICH WOULD BE AMAZING. Rokkies OT3 forever.
Of course, lots of the classic pairings are popular because they work well together, like Takagaki and Ishiyoshi.
However, it does put into question how Mikitty-based pairs would work out. Oddly enough, Takahashi's so good at adaptation in general that the Mikitty-Aichan pair would work, but otherwise, I can't see Yomiki or even GAM being that effective as co-pilots. GotoAya would be an ace pair, though.
As for the new gens, it seems like there could be an emerging fight for Riho.
I'd give the edge to RihoAyumi first and then RihoZukki, but RihoOda might emerge as a viable pair, a la Mikitty-Aichan, depending on how their vocals-duo dynamic develops. Even MaaRiho might be hilarious in the Conn Pod.
Ponpon is an obvious one, considering that pairing-wise, they're kind of the latest "perfect complement partners" pairing a la Ishiyoshi and Takagaki.
Man, I don't know enough about 10th gen.
Oddly enough, I can't visualize clear Kids pairs. They're all just so amiable with each other, and I don't get any particular team-up sparks. Rather, like with 7th/8th gen, it would be interesting to explore non-optimal Drifts, where they're compatible but not necessarily affectionate. They can work together, but it's not out of kismet of any sort. Pairs under this would include MiyabiMomoko, ChisatoAiri, and JunLin. As amusing as ChisatoMomo and JunKoharu are, they don't quite sync, and part of the fun comes from how they don't sync, and that disqualifies them as Drift partners.
More passive pairs would be the obvious ones like MaimiAiri, MaimiCaptain, ChinamiYurina, and MiyabiAiri.