Race Weapon Proficiency
I like what they did for the Multiplayer version of Vengeful Ancient and that it's similar to the Geth characters' Networked AI ability in that you get a 5% (10% if maxed at rank 6) bonus when wielding Collector or Prothean weapons (which isn't the only Prothean weapon the Particle Rifle?). Is gives you small incentive to use them but won't punish you if you don't.
This begs the question then, why don't all races have some form of this then? Why don't Krogan get a bonus using the Graal Spike Thrower or the Striker Assault Rifle? They're Krogan made after all. Infact many weapons have been made with similar designs to show their makers whether that be race (Salarian, Turian, Asari, Batarian, Quarian and Krogan designs) or faction (Cerberus, N7 and Blood Pack designs). Now I'm no game designer and this may be a stretch, but could a patch possibly be made for this? Bioware did say they're done with DLC for ME3 and I'll love their game no matter what.