I like the current system. It means you don't have to fill your pack up with a ton of potion bottles...BUT:

The amount of life/rage/willpower they refill is abysmal. I mean it's pitiful. A potion should refill more than just a small sliver. It would be nice if they refilled a % based on their potion level.

I actually like this system because it is simple and you can't rely too much on potions.

The potion drops are meant to upgrade your potions I think.

Personally one Health potion heals most of my health and I usually need 2 sips for Rage / Willpower.

If you potions suck try buying better ones at the merchant (they sometimes appear before you had them drop)