I like what you are saying and the justification for your decisions.
I do have a couple of questions though, how do you intend to grind out your opponent when you are giving them the early to mid-game. Surely you play catch up and then have to get lucky with Frost Lich Jaina?
I say this as Fire Fly, Pyros, and Tar Creeper are your 1-3 three slots which is alright, if you get all three in your hand but with only 5 cards to cover these slots you don't stand a good chance of curving out the beginning...
I'm thinking that in order to have a grindy mage with this expansion, you need Baku the Mooneater...Thinking about it more I'm going to include Doomsayer which will help us have a more consistent early game where you can then start curving elementals into the midgame. We also have Primordial Glyph and Book of Specters to play on two which both can help us have a solid turn 3 (discounted spell or drawing things like Tar Creeper). Other than that its possible that we need to include Plated Beetle in order to further help against aggro which even now is being done in mage deck to help them survive. Of course that does involve cutting some cards but I think things like Servant of Kalimos, Zola the Gorgon, and (possibly 1 or 2) Voodoo Doll could be removed in place of Doomsayer and Plated Beetle so I guess it would come down to which type of deck you would want to have a better match up against.I like the idea of Doomsayer. If you want to be using Doomsayer early, perhaps including Glacial Shard to help it go off?Plated Beetle does work! I've used it in the past to weather aggro. I'd say wait and include it like a tech if you need the extra help.