Think you should consider Lullmage Mentor as it would combo with Kira, Great Glass-Spinner well.

I considered running him for a bit, but I could never think of a situation where it would be more efficient to tap seven merfolk to counter something, rather than just slowing an opponent down with Cursecatcher .

Cursecatcher is good, don't get me wrong, but if you had a Lullmage Mentor on the field when you sac'ced it, you would get a 1/1 Merfolk token and not lose a creature in the process. Also, if you add in Merrow Commerce , tapping any number of Merfolk on your turn is not a big deal because they just Untap at the end of your turn, which means you can use them to counter whatever your opponent casts on his or her turn, which, also will net you another Merfolk token with Lullmage Mentor . in the end though, it is your deck. Just throwing suggestions your way.