Duel Lands: Adding any lands that produce blue mana without having the land type "island" would be very useful additions. Cards like Boil and Choke can be devastating to our mana base, so having lands that are harder to get rid of could work wonders.
Dissipate/Void Shatter: I'm toying with the idea of either replacing Supreme Will in the mainboard or finding a way to squeeze it into the sideboard. Being able to counter a spell and then exile it can come in handy, especially against graveyard decks. It is also good against cards with flashback like Faithless Looting and Lingering Souls, countering the whole spell instead of just half of it like a regular counterspell. The disadvantage is that Supreme Will can either counter a spell or help me dig through my deck to find what I need, while Dissipate is strictly a counterspell. I can also cast Supreme Will whenever I want to flip Thing in the Ice
wheras a regular counterspell needs to target and therefore limits my ability to flip the thing
Other Counterspells: this is where things get tricky. Which counterspells work the best all depends on what your local meta runs. Playing against a lot of tron and affinity, Ceremonious Rejection. Lots of combo decks, Disallow. Again, the counterspells that work best depend on what you're playing against.
Torpor Orb: This an interesting card in regards to Thing in the Ice
. With it in play, the thing enters with no ice counters, so the first instant or sorcery cast will flip it. It can also shut off opposing Snapcaster Mages and other important etb effects that might be harmful to our strategy.
Spellskite: This is a powerful card in regards to protecting our few, but important, creatures. Being a horror just ups it's value when Thing in the Ice
flips.
Distortion Strike/Slip Through Space: These have the potential to be very powerful in this deck. Being able to flip and clear the board, then bypass any blockers your opponent may have tried to cast can be game-winning. The only problem is that are a limited number of non-counterspell in this deck. If I try to add too much else the control strategy gets diluted and the deck loses it's consistency.
I really want to add Jace, the Mind Sculptor now that's he's lega, but I just don't think I can afford to play him early game, and if I survive to late-game I've usually already won and he would just be overkill. I also need a minimum number of instant/sorceries to make sure I can flip Thing in the Ice
, so there is limited room to add anything else.