Steam forums are a cesspit even by forum standards. It's Youtube comments level of discussion. I never go there or take them seriously. I play on difficulties 5 and 6 when in PuGs and most of my games are successes, once you get the mechanics the game's difficulty is just fine there. Of course sometimes there are dumbasses who run headfirst into automaton fire or throw stratagems on top of the team and get people killed but that's a skill issue that will happen in any game.
I do think some primaries could be buffed, but overall most do their job fine.
Stratagems is where the balance feels a bit more off for me. Most support weapons do have a role but many strats seem far too impractical for normal play. Maybe I need to test things more and not just always fall back to Eagle bombing run.