Freeze Mage is still a strong deck post-Karazhan, and this Thijs Karazhan Freeze Mage September Season 30 he was playing at high-legned on stream is proof at that.
Freeze Mage is one of the strongest torunament decks and I always recommend people learn how to play Freeze Mage as it comes in really handy to understand the deck if as an opponent. It’s hard to play however, you need to learn all the numbers behind combos of burn and how many turns you need to kill an opponent.
Practicse this list on casual untill you get the hang of it. It’s strong on ladder, especially with less Control Warriors in the current META than previosuly.