I just checked with Smogon, and oddly enough, he's UU. You're right; nobody really uses him anymore, due to the advent of awesome statusers and walls such as Gallade and Bronzong. However, he is still a reliable counter for Heracross, and Smogon's analysis points out that it beats Gyarados one-on-one. It can also switch into Earthquake from Metagross, Garchomp, Tyranitar, etc, and Burn them with Will-O-Wisp. Tbh I don't really see why he's UU, especially since Smogon talks about him as if he's OU, taking examples as to how he'd fare against OU pokes.
I now want to train a Weezing haha, since he seems so good. =P