First of all, Deo-N may resist Mach Punch, but he is weak to the rare Shadow Sneak. Not only that, but P-Z isn't OHKOed by things like Fake Out and Quick Attack (guess who is). But can we avoid changing this into a P-Z argument?Have you forgoteen 150/150/150? If Porygon-Z had 150 speed and resisted Mach Punch, it would be monstrous. Also, a crappy pursuit and countering 1 pokemon does not a success story make. Don't act so smug because your Spiritomb does 2 things instead of one
Since when is a STAB Pursuit crappy? Assuming they run the same investment, it is stronger than Scizor's. Not that all Spiritomb run max Atk, but the point is still valid.
For an analogy, Dusknoir was mostly out-classed by Rotom-A in Gen4. Rotom-A could do almost everything Dusknoir could do, and do it better. But Dusknoir was still OU.
Also, I am going to be very smug the next time a Rankurusu sweeps you. Because your closed-mindedness and stubbornness will cause you to lose.
Lastly, I don't even run a Spiritomb. So "my" Spritomb can't do anything because it doesn't exist.