In ME1, the squishier characters can be more manageable if you invest heavily in electronics early on. I have built Tali as a tank.
In ME2 I like to use Miranda because of her party buffs.
In ME3 there's the "Garrus ascends to godhood" build. That said, even on insanity I think the game is not especially difficult when playing as an infiltrator, so I just pick whoever I like.
Liaras biotics end about every fight in ME1 before it even started.
Tali is a Tank if you update Quarian Machinist and get the Colossus Armor in BDtS.
I could go on, but IMHO there are no "Bad" squadmates in Mass Effect
It all depends on how you build them, how you manage them, what mision you are in and what your Shepard's class is, and that is true for all games imho.
