How to Play the Quarian Engineer?

The Quarian Engineer

Salarian and Geth Engineers are really fun to play, and they are quite effective against any of the enemies. Quarian Engineer seems like a fun class at first, and spamming Cryo and Incinerate is fun for a crowd control, and gives the whole team easier time to take down multiple enemies. Combined with other engineers it works well.

But I find the Quarian Engineer quite powerless in some situation. If your team is just shooting and nobody is spamming energy drain or overload, you're screwed against shielded enemies. A single Marauder, Pyro, or Centaur will kill you fast on silver if your teammates aren't right there. In short:

Problem: Quarian Engineers powers are useless against shielded enemies

Solution: Carry a big gun? But that will mean less cooldown, which means that the Engineers support role is diminished. If I want to carry a heavy gun, I'll just play an Infiltrator or something else.

So, how to play the Quarian Engineer efficiently?

TL;DR: Quarian Engineer lacks ability against shielded enemies, how to deal?