Nothing is really all that cheap, there are ways around it. For one the knife and the lancer (Or ANY melee weapon in an FPS). . . well do I have to point out you do in fact have a GUN.
Are there ones that piss me off to no end? YES. In GoW it was the shotgunning idiots who thought it was the only gun. The chainsaw was no where near annoying as a shotgun shot from the hip that could instant kill you from medium range (Or far range could down you if they got lucky and some shots went into your head!) In CoD it's commando, I will defend knives till the end, but when a game has to lagg because not everyones connection is perfect, don't make a move that turns someone into Goku. Honestly if I get caught from the front by a command perk, it's because he ate ALL my bullets (I've even heard my shotgun go off looking straight at the guy and he gets off scott free, no red screen even). I also can't stand thermal scopes, but that's only because your weapons have heat signatures apparently.