I cant stand reading the people complaining about things being OP. It is a fucking co-op game, it isnt competitive. They should make the classes fun to play and not worry so much about is class A better then B. I wish they would make more classes OP, I want to do solo plat runs.
The problem with weapons/characters being OP stems from the fact that they trivialize the higher difficulties and that they foster inexperienced, uncooperative players into extremely detrimental habits: not using medi-gels, shooting at the same thing every one is already shooting at, not participating in the objectives, not rescuing teammates (why bother, when it's a given you can run an entire 11 waves by yourself).
This is why Gold matches full of infiltrators, Kroguards, geth soldiers and N7 characters start like speed-runs for the first 4 or 5 waves, and then turn into full scale fail in the 6th wave where all players drop like flies.
I'm with you when it comes to score issues, but the fact is
exactly because this is a co-op game no character should be able to face on his own a game supposed to be challenging for four.
The reason why missions fail is always the same: every new-comer, casual player wants to be top-score out of the blue, so instead of being tactical about positioning and which enemy to target first, they just shoot at the next big thing about to go down.
So you have teammates who keep by themselves with their harrier X until they can, then kite Banshees and Pretorians to the other players when they chicken shit.
And when this happens, lo and behold, instead of taking care of their own mess they start shooting at the Atlas the other players spent 5 minutes tearing down.
This a great game (MP) where awareness based on experience and synergy between equipment and characters' skill do the talking: OP characters and OP weapons turn it into a joke and make it look like the usual after-thought, unbalanced MP you find in just about every 3rd person shooter title nowadays.