Only 1 thing?
I would like to mention several. But well, here’s the top one for me:
Bring back ranged SV, as a 4th spec option!
EU link: [Suggestions updated] Pre-Legion Survival [4th spec]
MMO link: https://www.mmo-champion.com/threads/2490341-Suggestions-updated-Pre-Legion-Ranged-Survival
And like I said, there are more things I would like -to be changed/added- for the class.