Hmm.. funny. I used secret mage as well to get to rank 4. Didn't bother to get any further, the game became repetitive and I saw a lot of counters against secret mage (yes a lot of frustration for Eater of Secrets and kezan). Also I had to play a lot against other secret mages. So much, that even as a secret mage myself, I included kezan for countering the mirror matches.
But I don't think the deck is a problem on its own. It is really strong yes, but so are other aggro decks like mech hunter and odd paladin. And there are easy ways to counter the deck, which is happening a lot right now. So I don't think there is a actual problem.