That's the cool thing about ME3 compared to ME2, each class is far less pigeonholed into a specific built pattern. Cloak gives a damage bonus to your powers and if you don't take the 'Bonus Power' evolution, you can cloak, immediately cast a power, and that power's cooldown will be just 3 seconds regardless of your weapon weight or other cooldown bonuses/penalties.
Similarly, the Infiltrator makes for an interesting caster. You can beat the entire game without firing a single shot (outside of mandatory sequences like Eva Coré). Amplified Concussive Shot with Incendiary Ammo is the only skill in the game that can both prime and detonate its own explosions, so you can pretty much just drop your cooldowns as low as possible and spam that one skill all game long.
