>>247675721. If your attacks missing is a problem, go for a team centered around a setup sweeper with accurate moves. Less power for more accuracy is offset by using Nasty Plot / Swords Dance. Good options are Mega Pinsir and Thundurus (Therian or Genie are both good for this).
Next you need proper support. Pinsir struggles against Rotom and Skamrory, so throw a Magnezone and a Celebi on your team to counter them. If you went with Thundurus, you could use Taunt Gengar to put a stop to Pink Blobs that would wall Thundurus. All of these pokemon have very accurate moves that are unlikely to miss. Lastly, Whimsicott can help you setup by Encoring an enemy into an undesirable move, or by using Memento to force a switch.
If the problem is opponents getting lucky with crits and shit, I'd suggest simply using a Hyper Offense team. If you go fast and kill them quick, they won't have many chances to make you flinch or burn you or whatever. Mega Lopunny is probably your best bet for what to center a team like this around.
