More thoughts (sorry for rambling)-
In response to the "it'll invite trolling" argument I've seen before, I don't think that's really fair. The people that would target those with differing pronouns or create wild caricatures were already people that had no interest in following the rules surrounding bigotry. I actually have seen people make their character dark-skinned for the sole purpose of RPing a racist caricature; it'd be weird to argue we should only have light skin tones available in character gen because of that. The people using these features in bad faith aren't generally so subtle about it that avoiding it altogether "just in case" makes sense. A transphobe will just be transphobic if they want to be. Blocking features that people may genuinely like and make use of just because of a small handful of theoretical bad actors is, in my opinion, just letting them win.
As for writing lore about alien genders being too "weird" or "dumb", I don't really think gender is inherently any weirder, more taboo, or more convoluted than anything else we've had in the lore. "Here's this specie's unique genders as defined within their species, here's how they're viewed within their own society and without, how their different views may clash with other cultures, and how interacting with other species has changed and influenced their own perceptions" is all potentially very interesting to explore; and if you don't personally think that's interesting, and would rather RP your alien as a man or woman rather than a smorp or a plorp or whatever, that's fine. We're MRP; there's no rules on the server enforcing lore compliance. Nobody's gonna hold a gun to anybody's head and force them to be a plorp. You can just be a man or a woman and you don't really owe anyone an explanation. If you need an explanation, though, you could always just say your part of the planet adopted human ideas of gender due to cultural exchange, or your character was a cross-species adoptee, or your character's trying to fit in better with a majority-binary crew, etc etc etc. Really, if the very idea of "aliens with non-standard genders or gender roles" makes you uncomfortable, there's nothing forcing you to engage with it, and there still wouldn't be even if it was part of the official lore.