deathclaws scale up with you, at least i think so
at level twenty, wearing tesla armor, they were taking huge chunks out of my ass with one swipe, and it took several missiles to down one
also, go to old olney and see if you still think they're pushovers
once you hit higher levels mirelurks are easy, you don't even have to aim for their face
i found giant radscorpions to be more of a pain in the ass than any other enemy - not because they were hard to kill or anything, but at higher levels those goddamned things are everywhere, and they come at you in pairs, and if you're not paying attention they come up behind you and commence lighting your ass up a few times before you can turn around