Legendaries in RP

A simple question... with a tricky answer, is legendaries okay to use for RP? (not as the items they are but rather... as a transmog being something else.) also... which would they be okay for just RP?

You can use what you want as transmog. You might have a weapon based on a legendary for example or it may just resemble one.

I don't think the... (what was its name again, brain freeze, you know... the chat spam weapon. thundersomething) is useable.. it is a bit TOO flashy

People use weapons that are too flashy and too impractical to ever be an effective weapon IC all the time. Partially because fantasy weapons are absurdly modeled, and partially because most people don't know any better. Personally, I try to ignore that most weapons in the game are the size of a small child, have far too much width (and therefore weigh far too much), or have other seriously impractical design flaws. It is fantasy, after all.

You can't transmog legendary items

if it looks cool, why not use it?

I mean. You physically can't transmog legendaries. The game doesn't let you.

You can still equip the actual legendaries.

Indeed. it wouldn't BE the legednary IC I would just use the amazing model for example am I grying to get the hammer of the maker... for my holy IC priest