I have a crazy and fun idea...
How about if there was a set with the 5 item bonus being the ability to turn into the mob/boss you're attacking for 5-10 seconds. You'd look exactly like him and be able to use some of it's abilities.
It's kind-of useless but it would be a fun thing to play with XD. I'd go fight the nearest Dragon-like creature cos I love dragons so much

. Actually, turning into any animal/non humanoid creature would be fun.
I just wish there was the possibility for a druid-like class. I love taking other shapes and Werewolf form isn't permanent

. But , as far as I know, the lore doesn't allow it ... does it?