After getting reload hiding and cancelling down pat, my latest go-to for relaxing in platinum is now Geth Soldier (Flamer & Fort, No Hunter Mode [keep shields intact]) with a Raider. Lack of mode + any cyclonic will keep you alive longer than most others, which I find better than dying in 2 hits but having better damage with hunter and/or Power Amps. As a PuG, it just seems better as most people flail around the map doing random stuff so may as well consider yourself solo half the time.
The words "Thunk Thunk Whoosh" sum it up perfectly. Might convert from flamer emphasis to weapons seeing as the Raider is used primarily, with mere half-second flames inbetween to rel-cancel and dunk armor, but the main thing stopping me is lack of credits // lack of shotgun amps to make it work properly, so may as well keep the flamer emphasis for now. Raider without amps is pretty boss if you're consistent with the rel-cancel / rel-hiding to spew out two shots every second constantly but it bloody massacres your ammo.
Alternatively, I've taken a huge shine to the Asari Huntress Infiltrator (Raider again) for when I want moar blueberry toe-nations instead of white-hot whoosh'n'thunk dunk.