That's a little different though. I've always seen Biggs and Wedge as more as an easter egg than anything. They've honestly come to be their own characters in the FF franchise pretty much only sharing the name. I wouldn't exactly say it's a crossover when they're not specifically from Star Wars.
I actually agree with the OP and I normally take this stance whenever this topic comes up. I always use PSO2 for example. For those who haven't played it, it began an a sucessor to PSO but then they began having crossovers every freaking month. Anything from Godzilla to Guilty Gear and even FFXIV with Odin randomly showing up as a boss. No backstory or anything, just cool costumes and weapons for your character to win in a gatcha (with real money) or puchase from the market boards and an Emergency Quest where you fight Odin himself. Even now, the game has lost it's identity going from a game about space mercenaries to becoming a high-school, shonen to a high-fantasy game. FFXIV already doesn't really have an identity that much outisde of it's story, cities and some of the characters as most of them are from past games anyway. It's basically a melding pot of FF and SE at this point which I actually enjoy. But the "this person/creature is from another world" thing is getting old.
As far crossovers go, I'd be cool with games that fit the mold of FF. Valkyrie Profile, Bravely Default, past FF games, even some of the mobile games like Mobius and Exvius. I'm still hoping for a Chrono Trigger/Cross-over. The Dragon Quest crossover was cool because DQ and FF are so similar that it fit right in. MH was ok but I feel like it didn't work well having a fight similar to the actual game without the actual gameplay mechanics. Nier feels really dumb...someone mentioned DMC some weeks ago which I feel would be out of place. I enjoy the game as much as the next person but everything doesn't need to be crossed over with.