I really enjoyed the game, but having to stand still in real time for recovering stamina after fights as a paladin was just horrible, I sometimes went cooking while the game ran... Since he loses stamina all the time for being hit or hitting something in melee, there are never enough stamina potions no matter how many gallons you shove down his throat.

I look forward to play the game again sometime, but the balance should really be patched (paladin is way too hard).
Is there some trainer or patch for the awful stamina system? It's a bit too realistic imho.

I'm afraid that there is no trainer or patch for this, and as far as patches go, I'm not sure that this will ever be patched. Mainly because that would require digging into the code itself which is something the developers consider too risky after all the years the code was compiled for the last time.

A possible work-around for this could be to use the command console:
- press ~ (next to 1)
- type \givenewpotion t
- press Enter.

This will give you one Stamina potion. You could also type \heal x (where x is the number of Health, Mana and Stamina points recovered).