It's long been said (or so my understanding is) that there won't be Geth Vanguards or Adepts because synthetic beings can't use inherehntly-organic Biotics. Something about Biotic Charge causing a Geth to smash into a million tiny pieces.
But now we have Havoc Strike, a non-biotic method of slamming into something with extreme kinetic (and igneous) force without fatal consequences. Considering that, do you think we could see something along the lines of...
Geth Shock Trooper
Havoc Strike
Defense Matrix (Currently only available in singleplayer on EDI or as an EDI-granted Bonus Power, but the closest thing I can find in ME3 to ME2 Legion's Geth Shield Boost power)
Flamer -or- Electric Slash ... or Hunter Mode
Basically the idea would be the Geth enhances defenses with Defense Matrix, blasts into melee with Havoc Strike and then follows up with a powerful close-range attack, either Flamer for Fire Explosions or possibly a Heavy Melee attack (which could be Hunter Mode-enhanced.) If there's enough enemy left to put the Geth in danger, this puts it in a vanguard-style high-risk position, where it will need to either rely on weaponry to finish off the enemy, or on quick maneuvering and Defense Matrix's shield-restoring function to allow it to retreat to a safe position where it can redeploy Defense Matrix and repeat the combat pattern.