By reputation, unpopular art design changes and bad performance relative to the amount of technical enhancement it received.

The art direction from the original developers was basically thrown out the window by the third party the publisher hired for the Spacers Choice edition. Basically they did the equivalent of one of those AI photo enhancement tools - totally changed what the characters were supposed to look like. That, along with a number of dubious visual “enhancements” were added that actually degraded the look and feel of the game. They also removed the level cap, which was just stupid, as one of the salient critiques of the original was that it was too easy. Pretty much any competent character build will so you essentially entering god mode by the late game. The only good thing about Spacer’s Choice was that it included the DLC, but it wasn’t even at really any significant discount compared to just buying the original and the DLC separately. Add to that performance issues at launch that didn’t exist in the original and not really sure why anyone should bother.