No. Plot is what makes world dominance possible.
Even with a level 20 wizard, you have limited spell slots, meaning you must divide up your ruled state in to pieces for sub-rulers to govern. Else, even as a wizard, it's just a bunch of tedious work to check in on every region and make sure there's no rebellion or whatever. Divinations make it easier, but as mentioned, it requires spells. Not to mention there are ways of negating Divinations (I think Mind Block does).