Yikes. That svcks. Sounds like Oblivion's followers.

It's probably just their "role", though. I just went on UESP. Accordingly, as described by UESP...

Farkas is a Nord member of the Companions who has a reputation for being a skilled warrior, if a bit slow at times

Vilkas is described similarly...so we have a couple big, dumb warriors. Probably great in a battlefield situation, but I'd hardly expect them to be good at stealth.

Try http://uesp.net/wiki/Skyrim:Jenassa. She's a ranger and like I said, she stealthed pretty good. The only downside was her fee of 500 gp, but I personally don't consider this a downside. She's well worth the cash, and

a follower can die from anything. when a follower reaches 0 health, they fall down and immediately lose all aggro. a single point of damage will kill them. usually, it's because the player accidently hit them, but sometimes they can be killed if an aoe attack catches them, or if they have been poisoned (falmer use lots of poison)

They implemented a nasty disease effect that you get when you use followers.
It makes your nervers overload and die and encourages you to bite into nearby objects.
Drinking lots of Mead may counter that effect to some extend however.

:rofl: