After the recent discussion of enderpearl use, I looked through the Bukkit Plugins, and found a plugin I think would provide a descent solution to the problems raised.
http://dev.bukkit.org/bukkit-plugins/enderpearl-cooldown/
This plugin provides permissions, configurable cooldowns, and optional costs for use of enderpearls. I expect that setting an appropriate cooldown will be all that is needed, as this makes glitching through doors more difficult, and could keep someone killed by defenders after using an enderpearl to scale a wall from returning immediately.
http://dev.bukkit.org/bukkit-plugins/enderpearl-cooldown/
This plugin provides permissions, configurable cooldowns, and optional costs for use of enderpearls. I expect that setting an appropriate cooldown will be all that is needed, as this makes glitching through doors more difficult, and could keep someone killed by defenders after using an enderpearl to scale a wall from returning immediately.