xp for gold means you get less for killing a monster than you do for robbing it, and encourages a more careful exploratory approach. Modern D&D is much more of a tactical combat game than the original, where encounter design is "balanced" based on the assumption that players will be able to kill what they run into.

> Modern D&D is much more of a tactical combat game than the original

Kind of ironic when one thinks about it! Also, depending on how one defines "the original" this statement can be impossible to be true.

(not at all disagreeing, it's one of the things I don't like about the modern game)

Was there a different xp mechanic between AD&D's gp = xp and 3+'s only killing is xp? Because I don't see how the switch to that could possibly reduce the incentive to murder.