So I really hate how all the rages besides unchained Barbs rage can kill you from the HP when you go out of rage.
What do you think of changing it to this? Would this make rage more powerful or keep it the same?
Raging:
For all class rage abilities the bonus hit points granted are temporary hit points that are lost first when a character takes damage, they disappear when the rage ends, and are not replenished if the character enters a rage again within 1 minute of her previous rage.
It'll only cause problems if rage powers/class abilities interact with the same morale bonus to your statistics, so house rule those appropriately and you should be fine.
My brain is failing to cite examples at the moment however, so it might not even be an issue.
Why would this be a problem? It's not a problem for unchained barbs?