2x Exp events hardly collide with Mirage opening times, especially since Mirages open once every few days. I think this makes mirage even less attractive than it already is, as it's the only leveling spot you can't take advantage of during exp events (likewise it's the only leveling spot which isn't open 24/7).
I think to make this more fair, the next few instances of each mirage after an exp event should have increased exp, if it's possible to increment such a thing.
I think to make this more fair, the next few instances of each mirage after an exp event should have increased exp, if it's possible to increment such a thing.