Why are the Gundams in Endless Waltz different from those of Gundam Wing?
Everyone seems to be confused on this matter. The Gundams in Endless Waltz were not upgraded at all, they are just another rendering. The Gundam designer from Gundam Wing made his own designs for the 5 Gundams, including the Epyon, Tallgeese, and the Tallgeese II. But, that designer left before Endless Waltz was ever made. So Sunrise got another designer to do Endless Waltz. This particular person didn’t feel right using someone else’s Gundam renderings, so he simply made ones of his own. So in his view, Wing Zero always had angel wings, Sandrock always wore a cape, Heavy Arms has 2 Gatling Arms, Deathscythe Hell looks like Batman, and Alto-Long always had the red wire dragon fangs. I hope this clears up any confusion on the matter, feel free to e-mail me if I haven’t already answered your question in the above paragraph.