AI aggro control problem

I'm making an AoS and suffice it to say the creeps and defensive towers have vendettas against heros. After thinking it had something to do with the unit stats in the editor i modified the only one I could think of that would change the way the AI acted towards them and I increased "Stats - Priority" but either there was no change or not a change enough for me to notice.

What I want is the creeps (owned by the opposing computer players) to have a similar hate control to the ones in dota -- but maybe a little more aggresive towards heros I havn't decided yet --.

I'm not sure where I remember reading this, but I think if you set a unit's level > 5 it prioritizes targets more intelligently, like firing on the almost dead first then the heroes. I'm not sure if that's exactly what it was, but it wouldn't hurt to try setting the tower level to 6 and seeing what happened.

Also, I think Priority modified the unit's rank in list when you have multiple selected.

Wouldn't that also increase the experience gained by the heroes? Because I wouldn't want to have to go fiddle around with the exp tables in the gameplay constants window. But, if I must then it cant be helped *shrug*.