>>43086187TR users either self setup and have the defense to do so (the equivalent of +6 speed in one turn) on top of utility or flexibility or being able to functions sans TR if it ever goes down. All Octillery Clinton has is coverage and that's it. Sniper is shit and suction cups isn't that good on it since it does not have anyway to buff it's offenses.
All good mixed attackers that are relevant in their tiers have high BP move, abilities and items that help make up the deficit of spreading their offenses around. Octillery has no physical moves to abuse for physical coverage outside of poison , water, grass. Meanwhile If Nidoking got Gunkshot and a 90bp physical Earth move that's meshes with Sheer force it would go mixed to some degree instead of the still very potent special wallbreaker it is in gen 7.