Back then patching was limited so the norm was just to release a fighter again with some kind of expansion.
As for the Alpha series, yeah there's a difference depending on what you are looking at. They all are visually similar with just UI changes between but gameplay wise, Alpha 1 is kinda jank and everyone ignores it and continues to play 2 and 3 instead.
---
http://i649.photobucket.com/albums/uu215/chitlins_and_grits/_Raich_.jpg