Preface: I know the OW2 will be the exact same game but v1.1 with little better graphics, but here are my suggestions and add yours:
4v4 permanent Comp mode for soloques only. 1 tank, 2 dps and 1 healer.
It will work, has worked in other games. Makes less reliant on a huge ball of teammates working together, easier to identify problematic players in solo que and compensate with your own actions.
Ultra wide support like in CSGO. It doesnt give you an advantage, otherwise everyone in CSGO would be playing with it.
Better tick rate, theres too many times in FFA or comp where i run through the enemies arrows and shots, but dont get hit. Neither does it feel fun to shoot soldiers helix and have it canceled mid flight.
PLEASE SUGGEST your own ideas too so Blizzard can consider a few of them.