Major changes are
(Ring of Frost / Ice Ward / Frostjaw) Now on Tier 3
Tier 1 is now the movement tier, Scorch, Ice Flows (exactly the same as Arcane Flows) and PoM
Swapped to Tier 1, so now T3 has RoF / Ice Ward / Frostjaw, just to note Ice Ward's wording makes it sound like we may be able to cast it on friendly players which could be interesting.
Cold Snap now also gives 10% mana back so made it marginally useful again, at least for Arcane. other than that it's now the same
Completely scrapped Dragon's Breath / Slow / Blast Wave.
Now we have 3 different "Bombs" Arcane, Living and Frost.
Living Bomb is the same as it's always been
Arcane Bomb, does single target damage and applies a dot, however it can "jump" to another enemy mob within 15y at any time, so it's unpredictable.
Frost Bomb, 5 seconds after applying it the bomb explodes dealing aoe damage and creating a 70% slow.
Both Arcane Bomb and Frost Bomb are quite interesting to me, with Arcane Bomb it will most likely end up being top for single target but if it also does damage after each jump then it could also be better for cleave fights, but less predictable and so subject to RNG.
Frost Bomb, means you would have to be relying on the enemy to move into range of enemy's, though potentially this could be nullified in PvP, for the most part I don't think it would and a ranged 80% slow, that's pretty damn good imo.
In summary I do like the changes, especially scrapping the final tier, though I'm worried that I can't find Slow / DB or Blast Wave in the Spells list, I'm hoping it's an oversight on Blizzards Part, They are making good progress with the Mage tree but some tiers still seem incredibly weak, Tier 2 (Mana Shield eurgh, Blazing Speed needs to not have movement impairing effects compulsory for use) and Tier 4 (GI needs a shorter cooldown, 5 minutes! and also to remove all dot's without it it's fairly useless. Cold Snap still needs to refresh cooldowns on Ring of Frost at least)