Though I don't agree with the OP's definition, I think your logic is a tad flawed. What if omniscience arose as a consequence of omnipotence: god knows the outcome of all events because he chose the outcomes. Sort of like an author knowing the end to his own book.
I didn't mean to get overly bogged down in the idea of fate here, but yes- for a god to be omniscient, I'd think we would have to be confined to a foretold or pre-set path. Before you grill me too much about this one, I'll say that I don't believe that there is an omnipotent and/or omniscient being.