I think we should allow Wynaut into OU for now simply because it really hasn't had a chance to be tested in the standard environment yet. However, in addition to SDS's post, I'd like to say that Wynaut is actually extremely effective in UU. There may not be any strong Pursuiters, but there is still Trapinch with its 100 base Atk, and after 6 Tickles that EQ will OHKO pretty much everything.
Personal example here, but Wynaut can easily switch into a Steelix and Encore its Stealth Rock, then proceed to Tickle 6 times, Encore SR again, then switch to Trapinch. Trapinch can set up a sub and then EQ Steelix for the easy kill. After this, you'd be expected to bring something relatively bulky (read: slow) into Trapinch, as a pokemon with 100 with a STAB EQ behind a sub is a pretty daunting aspect for most sweepers. As far as tanks go, Milotic is one of the fastest ones. Trapinch can use Rock Tomb on it. At -1 speed, a base 90 speed pokemon with no speed investment is outsped by a Wynaut with a neutral nature and max speed. Wynaut can then either Encore the Surf and Mirror Coat back, or simply use Destiny Bond (as was done in my battle) and take out the slowed down wall.
I waffle, and maybe this isn't the best place to discuss Wynaut's placement in UU, but I'd just like to point out that I believe it encourages hyper-offensiveness in the metagame by taking out any wall with less than base 60 speed, and the majority of pokemon after a speed drop otherwise.