Inner focus, with the exception of Lucario, can't switch in, and if they can it doesn't help much. So, from my experience, this guy is much more helpful.
Shedinja @ Focus Sash
Ability: Wonder Guard
EVs: 4 HP / 252 Atk / 252 Spe
Hasty Nature
IVs: 0 Def / 0 SpA / 0 SpD
- Will-O-Wisp
- Shadow Sneak
- X-Scissor/Protect
- Sucker Punch/Protect
It can switch in, annoy the enemy, and, when the game is near its end, beat the enemy completely because they cannot hurt it. It greatly benefits from this meta due to the prevalence of fake out and the easy switching.
The moves are fairly obvious. Will o wisp punishes switches, while, shadow sneak provides an attack and a fast switch. X-Scissor is a far more powerful attack, suitable for punishing switches. Sucker punch, meanwhile, allows you to pivot out from normal types. Protect is another option- It allows you to scout and see if the enemy is capable of harming you.
While rock hurt it, this mon also benefits from the Lati twins, who can use scarfed Draco Meteor to punish the meta. Since defog also switches them out, they can easily remove rocks and pivot Shedinja in.
Of course, it isn't without flaws. Talonflame doesn't care what this guy tries and punishes any switches, while rough skin makes it dangerous to attack. Similarly, it will die to random rocky helmets.