trying to think of anything good this game brought to the genre, and the only thing I can think of is how it handled factions via quest completions. like you're fighting dudes and eventually make your way into their base, do the little boss instance and you beat them, little story scene plays out you are the champion they are on the run etc. when you go back to the overland area the npc's are no longer aggressive to you.
This is the first game i've noticed that did that but it's possible i'm miscrediting them for it. At the time I thought "ah that's neat" but now that i'm back to playing SWTOR I find myself thinking "man they really should have that thing that wildstar did in this game, it would make so much more sense"
And that's really the only thing this game did that was a good idea. The only other good thing I could say about this game is it launched with a lot of content and features. Like they knew what it was, and what it was competing with, and they knew they'd need a lot of shit to compete. unfortunately it wasn't enough of course.
I imagine since it's mostly former blizz guys who made this game, they probably had the same design principles as blizz when they were building this thing. I imagine at some point a year or two into development somebody was like "hey guys, is this game fun?" and it was like a unanimous "um, not really?" around the room. At that point blizz would just can the whole project but now that they are independent and don't have dumptrucks full of money to start over with, they had to make it work. So while they tried and (imo failed) to make the game fun, they definitely just kept adding features to cover up the lack of fun.