While it may be fun (I can't say as I never used it), Rock-It Launcher is a completely unrealistic weapon. I mean come on, you can't decapitate a super mutant with a friggin teddy bear no matter how hard you launch it.
If I were a modder and I wanted to add it back in New Vegas, I'd make it Wild Wasteland.
A Super Mutant however, is also not tooo realistic.
The makeshift weapons were a pretty awesome concept. The Railway Rifle in particular, was super fun. Pinning Muty heads to walls was one of my favorite things in Fallout 3.
I was surprised they got mostly sacked, given the overall emphasis they put in crafting in general.