I've been experimenting with many different gothitelle set-ups at the moment. So far, the specs has worked the best, as it kills walls like gliscor, skarmory, politoed, jellicent, and amoongus, kills revenge killers like breloom, scarf terrakion(off the death fodder of course), tornadus, tornadus-t, thundorus-t, and scarf landorus(not in sandstorm). Also, it can cripple many stall or set-up pokemon by tricking it your choice spectacles(Ferrothorn, Gastrodon, Reuniclus, Chansey, Blissey, ect). With my current set I've been running(to some somewhat great succuss) I run this-
Gothitelle@ChoiceSpecs
Trait-Modest
EVs-212HP/252SpAtk/44Spd
Attacks
-Thunderbolt
-Psychic
-Hidden Power Ice
-Trick
This gothitelle was specialized around getting around threats big to physical attacks, such as gliscor, skarmory, and slowbro with trick.
I've tested the substitute,protect, torment, taunt set, but Trick seems to do that all in one. Also, this set miserably fails if the staller has 2 attacks, and then gothitelle becomes completely useless. The scarf set had damage that was, well, very underwhelming. The specs set feels like gothitelle is hitting as hard as a normal maxed out special attacker, so scarf makes it feel like a sunkern in OU. There isn't really much it can outspeed and 1 or 2 hit ko decisively. I find Gothitelle only can find spots on teams hurting vs. stall, or a heavy offense team that just needs a hole opener.
I'm going to be testing a Calm Mind gothitelle latter today. Too bad she has no recovery:(