Merchant Scroll might be a better option. It gets ancestral, brainstorm, fof, thirst, force, echoing truth, etc.
IMHO, Merchant Scroll is Another option, but not better. It costs twice as much, is a sorcery, and doesn't get tinker. Merchant Scroll is more of Mystical numbers 2-5, but it doesn't mean you can cut the mystical for it.
And because this is the Vintage improvement forum I'll reiterate one point. Mono-Blue decks want to avoid tapping their mana on there own turn so as to mana available to counter on their opponents turn. IMO, Merchant Scroll is good card that promotes bad play by having players tap mana at the wrong time, for what is often times, the wrong thing.