As strange as it sounds; WBMM in my opinion for Native was detrimental. All of the known top players for years spent their time on IG_Battlegrounds, because there was more people meaning you had to block more and kill more. When WBMM released sometime in 2017, it killed IG; even to this day there's been few 'top players' that came from practicing on WBMM, all the well known top players came from IG. WBMM now is left with eastern european and Turkish players.
In NW, it's probably the same, you think you want it but you probably don't. NWMM is just another way to be frustrated, you can't always join the team you want to join, you can't have a casual experience, players trolling would make you lose MMR (unlike GF server where it's a more casual experience) and then you continue to do more competitive GFs with your GF team or regiment. There has to be a balance of casual, and NWMM would just kill it.
Leave the sweating to regimental or team GFs, NWMM is never needed and would only be detrimental. The best Native players came from IG, which is a semi-competitive server and not WBMM.