Even in the original the characters still don't really seem to respect her, and the game treats her as a male. We really don't have to settle for this as representation, we should demand better.
It wasn't perfect, but simply by virtue of passing Erica is a more positive representation of a trans women than 99% of media. She is also happy, has friends, a legitimate romantic interest, a normal job, and is arguably the only mature and well-adjusted member of what is a very dysfunctional cast. Compare that to western media where Trans women are almost always extremely masculine and non-passing (and always portrayed by cis men if it's live action), constantly equated with over-the-top drag queens and middle-aged fetishist cross-dressers, and live extremely pitiable and miserable lives for the most part.
Trap "jokes" are offensive and distasteful, absolutely, but I would easily contend that the likes of Rocky Horror and RPDR (both of which are widely celebrated by the LGB community) are far more damaging to the mainstream perception of trans women than characters like Erica or Luka (who isn't trans but is arguably presented as such initially in S;G). The former kept me in the closet for my entire childhood and adolescence, the latter are actually relatable despite some poor treatment from the writers.