I'm sure we've all done it... A big battle didn't go our way so we load an earlier save and generate new seeds so that we win that battle. My idea is that a sphere of time mana (maybe Tier 3) allows the AI or human player (legally) to load an autosave from 5 turns ago using new seeds for e.g. combat. The AI would be triggered to do this if e.g. they lose a hero/big city/etc.