Gothitelle's a p good trapper, that's for certain, but it can't hit terribly hard and can easily be taken advantage of by specially bulky attackers like Mega Gardevoir, of which the CM variants set up in its face. Dark-types also aren't too kind to it, either. I'd say
keep Gothie in B or move it to B+. It's simply not on the same level as many of the B+ Pokémon.
Staraptor (B-) -> B+ | Speaking of
actually underrated Pokémon, Staraptor is another fantastic wallbreaker to add the repertoire of rising stars in OU ever since Aegislash packed its stuff and left for the gods. Seriously, this thing can hit brutally hard when Banded, which is easily its best use. As people before me have pointed out (and I'm also saying this out of personal experience), Adamant Band Raptor just hits brutally hard with STAB Brave Bird and Double-Edge, shredding everything that doesn't resist it. Here's a small example:
252+ Atk Choice Band Reckless Staraptor Double-Edge vs. 252 HP / 252+ Def Rotom-W: 252-297 (82.8 - 97.6%) -- 68.8% chance to OHKO after Stealth Rock
This right here is why Staraptor runs Adamant; that extremely high power output makes a huge difference between 2HKOs and OHKOs and all you need is to set up your Rocks and have Staraptor maul everything. It pairs excellently with Talonflame and Mega Pinsir to form a Flying Spam core, Staraptor crushing all the walls that need to be broken down to allow Talonflame or Mega Pinsir to sweep safely. As a last positive note, Staraptor attains perfect coverage between Normal/Flying/Fighting and in conjunction with its insane power, it's extremely difficult to switch in on. What keeps bomb burd down from being a total annihilator are its weakness to SR, its above-average Speed stat of 100, its relative frailty (85/70/60) and its common weaknesses to Electric-, Rock- and Ice-type moves. With Aegislash out of the picture, though, Staraptor has become a whole ton more impressive in OU.
Staraptor for B+. Kacaw.