Not only does this card function as an upgraded Divination, but The Everflowing Well, should its requirements be satisfied, turns into a powerful value tool that can turn mana dorks, or something of the like, into ramped payoffs
If an effect requires you to pay some amount of mana to prevent Astelli Reclaimer from being countered, as Divert Disaster does, that mana wasn't spent to cast Astelli Reclaimer and will not be taken into account
Several big cards here Serendib Efreet, Birds of Paradise, Wheel of Fortune, Mind Twist, Sol Ring, Wrath of God, Shivan Dragon, Fork and many others
Thats essential to trigger all your payoff cards, but it also impacts certain spells like The Tarrasque
Control and Disruption: Blue's inherent control theme meshes well with ramping