Agreed, especially since they don't have a quick energy regen ability like the other classes. I do like the shield strength of a tech though. With shield tweaks, a drone and a Reaper shield, plus the passive perk that gives them reduced vulnerability, they can really soak up a lot of punishment. Even better if you're topping them up with a vamp blade.
The major problem with shields is that you can't apply defence to them. You can protect your HP with armor, but not shield. And, since tech have very little HP, they are pretty much screwed once shields are breached.