the Jester
Legend
The high level is a problem. What about a limit of one per encounter? The potions don't work if you take more than one in a certain timespan.
It doesn't fix the fundamental problem of cheap healing at high levels, though.
IMHO the potion healing mechanic probably took a lot of thought to set up to avoid these problems. I don't see a need to fix them, and if a given party chooses to go short on leaders and healing powers, I let them live with their choice.
My 'fix' for a low-healing party is to remind them that it only takes a feat to multiclass.