Create a 8-second combat system that doesn't allow a player to regain health by sitting or running against a chair and wall for that matter. And if a player decides to run inside a building (no-pk) while in combat, give the player a 30 second debuff that states,"You've fled from combat and unable to perform any abilities. " It definitely would reduce laming.
In the end, be original. Stop copying World of Warcraft.