I don\'t know, I kinda like it. If you\'re smart enough to run away from, say an ulber, how come a tef can\'t be smart enough to run away from you? This could also bring different attitudes of monsters into play more. A more agressive npc would run at you when attacked, while a less one, or scared one would run away. Also, it could depend on your level, if an npc can determine an approximate of how strong you are, it could dictate whether it runs or stays. Also if a npc would attack you to begin with. A rogue could atack a new player, but if it sees a higher level character it won\'t as it would know it would loose, rather than now when it attacks just eveything.
Edit: teach me to leave the reply box open for two hours while I actually work at work.