I found two weapon fighting to be pretty good and a lot of fun. Sure it costs you the bonus action, but I find a lot of the time there isn’t actually anything better do with it than give someone a poke, particularly if it’s going to finish off a threat. Although most of the time, I’m mainly holding it for the special abilities towards the end.
It probably depends a lot on class. I duel wield with a sword bard with the two weapons fighting style (but not the feat to use bigger weapons). Also gave Minsk the ranger’s two weapon style and the feat for larger weapons just because I picked him up really late and had a couple of really good maces going spare. I think it suits him.
Rouges make really good use of their bonus actions though, so that might not be the best idea. As do barbarians, fighters and clerics (ie healing word).
