Ridley's Cohort said:
You may not agree with my opinion (or Forrester's) but your reasoning here is circular: Cleave works that way because Cleave works that way.
I don't know about circular, but my reasoning is not arbitrary. An AoO is a regular melee attack, it should benefit from cleave just like an attack during a normal attack action.
Really you haven't answered the question about why I can't summon creatures to attack my reach weapon wielding buddy to generate free attacks. That is the purpose of Cleave, isn't it?
Well, if you think in-game and not think meta-game, a mage who summons a creature to attack one of his comrades will probably be attacked by said comrade right afterwards, and the DM should probably force him to do this. A fighter will not be thinking "OK, this will give me a cleave to my other foe for an extra attack", he will be thinking "damn, what the **** is wrong with this guy, he's attacking me instead of the BBEG". That is why it is an exploitation of the rules, because the player is now meta-gaming his character instead of role-playing him.
