Flash of Insight

The selection on the front half scales with X: look at the top however-many cards, pull exactly one into your hand, bury the rest. That it puts a card directly into your hand rather than drawing it is a quiet but real distinction, since nothing that watches for draws ever fires. The more interesting half is the flashback. Recasting it costs blue mana plus exiling X blue cards from your graveyard, and that second X is what determines how deep the repeat look goes. The dig is paid for not in mana but in spent cardboard: a yard full of cast blue spells is the resource that funds a wide second selection, so the late-game look is bankrolled by the early-game grind. That moves the card off the curve and onto a deckbuilding axis. It wants a deck that has been doing nothing but casting blue instants and sorceries, accumulating exactly the fuel it later eats. The clause forbidding it from exiling itself is small but pointed plumbing: it closes the loop where one copy could feed its own engine, forcing the cost onto everything else you have already burned through. Selection that compounds with how thoroughly committed to blue you are, structured so that the deeper you dig the second time, the more graveyard you have to spend doing it.