I do not want to just blindly oppose you, so sorry if it might seem that way, but botting in World of Warcraft is largely possible because of the simple nature of the game interface. If you are using a heartstone, move along a set of predetermined distances, you will reach your destination, and you can just repeat this process. Up till this point, you needed no data to be analyzed, just blindly give inputs to the client. Now, you are at the point of farm: you just hit TAB, which targets the monster automatically - again, no input needed, just a simple check. Then you hit an attack - if no monster is targeted, the attack fails, so you move around almost randomly in a predetermined circle. Then you do the basic framework of a battle, inputting the usual rotation. Then repeat. Then repeat.
What I am getting at is that in WoW (and in most MMO's) you can set up a bot with very, very little feedback needed. Diablo III is nowhere near this in complexity. I know bots existed in D2 and still do, but we need to make a meeting point between these assumptions:
-Bad security, easy to rig battle system (an MMO with bad security)
-Bad security, harder to rig battle system (Diablo 2)
-Good security, easy to rig battle system (WoW)
-Good security(?), harder to rig battle system (Diablo 3).
I can totally see why D3 will be the game to stay relatively clean for a long, long time.