Was there any explanation why the weapons weren't chasing janova like the planet programmed them to... i remember prof. gast syaing in his home movies that they were supposed to be the "weapons" against janova, not cloud or the citizens of the planet.

I can see why diamond weapon was going after midgar because hojo stated that he injected himself with jenova cells, but that gives no reason why ultima was blowing up every city he can find (other then the fact that cloud had janova cell injected as well when he attacked mindel). Only with the assumtion that there were SOLDIER members in every town in the planet (because they had been injected with janovas cells as well as showered with mako) can i see ultima attacking everything.

Why don't they just attack the center of the planet where sepheroth is hiding with that giant jenove mostrosity?