Well, I don't have the expansion, yet, as it hasn't been released for PC so I can't say much about it.
I don't think it will appeal to players who are only interested in combat and leveling their characters, but it's a great addition for many players who take their role-playing very seriously and like to get into character. It's especially good if you're a console gamer and don't have access to mods. I think it's more of a 'nice to have' than a 'need to have'.
Hopefully, features like these will become a mainstay in the franchise and players won't have to wait for DLC to get access to these kinds of enhancements.