Why are a bunch of EVs in defense on the Spikes lead? I doubt they will help you live a Bullet Punch from Scizor (Which is like the only reason I would think about running that much def), so why are we forgoing overall bulk? Minds as well be able to take one non-stab special along with physical attacks if Sandstorm breaks your sash or something.
Maybe on the anti lead, you could slash T-wave with Encore/Uturn. That really fucks over opposing teams when something is asleep and paralyzed, and if it works, you get up rocks too. Down side is it can't attack, but then again, Smeargle isn't going to be doing any real damage anyway. Otherwise, good job.
Scizor's Bullet Punch does 90% - 106.4% to 252 Defense Smeargle, so that's a chance to survive after one bout of Sandstorm. 252 Defense also has some other merits such as always taking a Rock Slide from Aerodactyl and being able to come back in after Stealth Rock damage, and surviving a Fake Out + Night Slash from Weavile. If you think that 252 HP is better than 252 Defense overall in the case of standard Smeargle lead, get some examples of their usefulness over 252 Defense.
With Thunder Wave, I can definitely see how it can be useful. At worst, it'll go into AC. Thanks.