Well, Bulbapedia says that it isn't classified as legendary, and Bulbapedia rules.
Seriously, stats don't make the Pokemon. Rotom could just be like a trophy: somewhat difficult to get, but worthless once you have it. It could just be rare, like Beldum, or the Pokemon that you used to be able to get in the game corner(s).
My answer: No but yes. A certified and useless maybe.