CroCune is actually still really good, it has the bulk to take on most stuff and can be a good late game cleaner. That aside, here's a good one I've got.
Mismagius as a Ghost-type special sweeper vs. Cofagrigus
vs.
Mismagius's Advantages:
Better initial Speed: Mismagius has a solid 105 Speed to work with, outpacing most of UU bar Azelf and the likes. This means Mismagius can more quickly fire Attacks without the need to set up Trick Room every time. This also means Mismagius has room to run Substitute to avoid status, and always has the immediate Speed to work with.
Levitate: While not as useful as Mummy, Levitate means Mismagius is immune to Spikes and Toxic Spikes, meaning she is not worn down as easily, only by SR, as opposed to Cofagrigus losing quick HP every time it enters or immediate poison, to a lesser extent. This ability also means Mismagius is a viable check to Nidoking and Nidoqueen, something Cofagrigus cannot boast having the luxury of doing.
Taunt: Mismagius can deter setup opportunities thanks to this move, while also stopping Thunder Wave to cripple it. Toxic and Roar are crippling to Cofagrigus, however, Mismagius can avoid these moves thanks to it, that is, if you run this move.
Thunderbolt: Mismagius can fit this great move onto its NP set, and has the advantage over Cofagrigus here with it. With either this or Taunt, Mismagius is not completely helpless against Togekiss, which is something against Cofagrigus. This also means Mismagius can deliver a harder blow to certain Water-types such as Blastoise and Suicune, the former being especially useful since this aids Mismagius as a spinblocker.
Mismagius's Disadvantages
Lack of sheer physical bulk: Despite its immunity to Fighting, Mismagius is very frail on the physical side, meaning heavy physical attack barrages can easily make work of it. Cofagrigus has superb physical bulk to work with, and can thus be a better check against Mienshao and gang, while as a result it has an easier time grabbing the NP boost that counts.
Trick Room: While Mismagius can function outside of Trick Room unlike Cofagrigus, this move is just a really good, anti-metagame move that can be used as a supportive option as well. This means Cofagrigus can turn every fast Pokemon into a liability, while it also provides great support to slower Pokemon such as Escavalier, Rhyperior, and Snorlax.