Creature Heal spell only revives 25% health maximum, they respawn at 10%, at least three posts or so should be assigned to cooldown timer between heals, chickens may help, but not nearly enough to simply jump right back into the battle. You'd have to go to sleep or else spend an inordinant ammount of time healing yourself.
If Keepers are the ones exploiting it with Keeper Heal spell than quite simply they should know better. Perhaps a resistance to Keeper Heal is in order?
Fact is, Level Reduction is bad, and in my opinion it is something we need to find a balanced way around a harsh penalty there. Leveling is a slow process.