Personally, I think the speeding up/slowing down time would make roleplaying it a whole lot easier. I would that maybe she could see the future, but that's a whole lot like god-modding if you think about it. For example:

Ai closed her eyes to see what would happen in the battle, then smiled. Her best friend Mila, even though her magic wasn't very powerful and she was going up against a god slayer, would win by using trickery.

If you posted something like that, the god slayer would be forced to lose, and they couldn't do anything about it.