Nah man, Thundurus is a boss. D:
I mean, you may not like its design, but it actually has more competitive merit than Uxie because of its vast movepool, useful resistances, excellent/versatile stats, and general superior utility on teams (especially considering that Thundurus is a better Nasty Plot abuser). Uxie, unfortunately, is outclassed by the likes of Azelf too, who itself dropped to UU, while Uxie sits below that even. Thundurus > Uxie in all competitive aspects, but that's not to say that Uxie isn't just plain cuter! ^o^ Which is reason enough to make a profile theme of it, imo.
But yeah, I'd like to check out what Uxie set you're using if it's actually working for you competitively. o.o;