the arguments you guys put up are really weak imo "I've never had problems with Volcarona, personally."
The WHOLE point is to discuss whether it warrants a ban to ubers, not if you don't have any problems dealing with it [/rant]
On the other issue, I don't believe that volcarona warrants a ban. There are quite a few checks.
Phazers, unless last poke. volcarona always run quiver dance, though it would be awesome to see a choice specs user...hrmmm (plots) anyways...
Latio's LO Draco Meteor outright OHKOs volcarona, though leftovers Latios draco meteor should be wary, as volcarona usually run a lot of HP, and has a great base sp def, and has a good chance of tanking the hit, QDing up and bug buzzing for the kill.
Dragonite's ES 2HKOs all volcarona, though it should be wary of flame body. even if it does get burned, volcarona is usually at a low enough health that it wouldn't matter. Dnite should be wary of the rest set, as by then it will most likely have been burned and volca will be at full health.
Heatran's roar. if last poke, lulz volcarona will power thru with bug buzz. if sun is up and volcarona has at least 1 QD, heatran's Fire Blast 2HKOs.
Politoed. drizzle + water STAB. also toxic and perish song.
I guess tyranitar could be considered a check in some ways, as more players are running the sp def sets, but its 2HKOd if volca has at least 1 QD.
and all these are OU, and commonly used.