The reason I go into battle with my assault rifle, is that my Avenger assault rifle is at level 10 and has a level five stability improver and a level 3 clip extender.
Though along with that I either carry my level ten Mantis sniper rifle, or my level ten Katana shotgun. When carrying that assault rifle and either the sniper or the shotgun, my power recharge is still over 100%.
The reason people can't beat Gold is because at many times, Silver can be insanely difficult. On Silver, even if there is only one enemy near by, it can be damn near impossible to revive a fallen teammate.
I played 15 Silver rounds last night because I wanted to get one of those special N7 packs for beating it on Silver, but the closest we ever got was round ten a few times, though we could never get passed it because it would always throw out the hack objective, where enemies seem to spawn right next to the hack circle and they spawn up around two brutes and a banshee or sometimes two banshees and a brute. You can't just sit still while fighting those things, but the hack requires the players to be in the circle and there isn't enough room to fight those things in the circle.
Silver at times seems like it is on Insanity, and if that the case, Gold difficulty must be ludicrous.
Edit: And what, no love for Sentinels. I adored playing my Turian and Krogan Sentinels. Also, don't be bashing the Turian Soldier, that proximity mine ability is shear awesome when it has a good recharge time. Proximity mine, boom, bang bang, dead, repeat.