Do companions/henchmen ever become anything more than weak meat shields that can bash open doors and chests?

It seems like I have to revive these guys every few minutes, rather than complimenting my playstyle and helping me it feels like I'm babysitting them instead. : /

I do have auto-potion turned on and I have a nice stock of stamina/healing potions. They use these frequently and still die. -_-

You know, I read that a lot but haven't had that experience most of the time. It may be that I'm using the archer guy so for the most part he stands back and helps soften and clean up enemies while I run in and hit them. He will still, at times, sprint for no reason directly at a mage and explode, or run across lava, but when I see that stuff coming I hide behind a wall, make him stop (G), then do whatever needs to be done before letting him come after me (A).

So, in other words, make sure you pick the henchman that complements you. So far, if I was a thief or priest, the melee knight might be better. As I'm a paladin, the archer works fairly well despite obvious terrible AI throughout. Also make sure you cure poison on these fools or they'll gobble healing potions rather than an antidote potion.

I'm playing as a Priest so all my Henchmen are melee-oriented. : /

Also, it seems that the lower the difficulty the weaker the henchmen as well. I picked a lower difficulty because combat is honestly kind of tedious at times. I might just be doomed to this as a Priest on easy mode (especially with the dog and the henchmens' suicidal tendencies).

I've never had much luck with the Purge spell for healing poison, what skill level do you need before it actually starts removing poison?

me too. but sadly we couldn't. I only use them to distract the enemy :))

As a priest, and when you get an inquisitorial investigator to join you as a henchman, with the right abilities and spells to complement his favourite spell being cast, the inquisitorial investigator can help you clear rooms full of enemies with his lightning attack that can often outright kill or inflict heavy damage on all enemies in the area with each hit.

If you are playing a Priest, your companions are just meatshields. Keep them alive by having lots of potions on hand. If they are dying on you, you do not have enough potions. Here are some tips on how to play the Priest -

http://www.gog.com/forum/inquisitor/how_to_build_a_priest_in_hard_mode

I never had a companion die when I played. Hope that helps!