Something that is worth noting is that while this effect is killer against Ancestral Recall, it is even more killer against Brainstorm!
I think that's exactly why Plagiarize costs

in the first place.

I don't see this being so unfair in Vintage but at

, I think it might be insta-banned in Legacy, which in turn is probably an obstacle to it seeing print at all. And in Vintage, when it comes to leveling the playing field against blue decks, would this card really be better than Uba mask? That is the standard for comparison, after all. It seems to me that Uba is a better conceived hoser of Brainstorm/Gush/Ancestral/take-your-pick in that even though it can be abused with Bazaar, it can't be used
by blue decks against one another. In other words, as an Instant, I'd compare Knowledge Reflection to Red Elemental Blast; it was designed to hose blue but actually Blue decks are the most likely archetype to play it, as a sideboard option against one another.
So basically, the fly in the ointment maligning your attempt to level the playing field has been here since Alpha. What is the solution? I really don't know. I have a few general notions though, based on what has been effective in the past. First of all, I think in order for anything to level the playing field against Drain based control decks running instant speed draw effects unavailable to other colors, whatever cards are printed to hate against said draw have to be priced such that they cannot be splashed and merely added to the arsenal of the very decks they are trying to hate. In other words, I think the price of

is the biggest problem with your new card.

is also out of the question, imo, while

might not see play at all though I think it probably would still be fairly priced for what it has to offer.

seems pretty good in that a Drain shell couldn't splash it, but are there enough playable white cards in Vintage for a deck in the vein of Parfait to be viable? In other words, GW Beats couldn't use a 2cc counter since they aren't going to have the mana open and it would go against their general style of play. I just think the power level available to UB decks in Vintage is so incredibly high that very few hate cards can really make a dent. In Legacy however, your card becomes a lot more exciting.
I think that a

version of your card would be ideal as an anti-Brainstorm and co. hate card in Legacy, but in order for it to be truly viable, Land Tax would have to be unbanned first in order to open up the possibility of mono or heavy white control as an archetype. I don't claim to know what repercussions that unbanning would have. Maybe Mox Diamond would have to be banned in its place? One wonders.
On a side note, I've been fooling around for a while now with an anti-storm WW hate deck and I like that this could potentially counter Ad Nauseum, though I suspect if the storm player ever got to cast their AN, my deck would have already failed in its general hate strategy.