Frost mages have insane CC. Allthough I doubt how usefull it is to stack them. Beeq had great succes with 5 arcane mages in pve though.

Locks haven't changed much I think. They don't dominate and aren't underpowered.

Ele's aren't exactly strong. Changes I could find:

Lightning Shield and Water Shield can no longer be dispelled.
Unleash Elements is now in the Nature school, and thus can no longer be used if a shaman's Nature school has been locked out.
Water Shield has had its internal cooldown reduced to 3.5 seconds, once again matching other shields. The amount of mana restored when Water Shield proc has been reduced by 50%.
Fire Nova damage has been increased by 15%.

Elemental

Call of Flame now also causes Fire Nova to add 3/6 seconds to the duration of Flame Shock auras on targets that Fire Nova damages.

Lava Flows now grants a 30/60/90% haste buff when a Flame Shock effect is dispelled, up from 10/20/30%.
Thunderstorm now reduces the movement speed of players it knocks back by 40% for 5 seconds.


Restoration

Improved Water Shield has been redesigned and renamed Resurgence. When Water Shield is active, Resurgence causes critical direct heals to restore mana (Resurgence rank 2 is roughly equal to 150% of the old Improved Water Shield value when a Healing Wave or Greater Healing Wave critically hits, and scaled down accordingly for faster or multi-target spells).
Mana Tide now grants 200% of the caster's Spirit, down from 400%.


Glyphs

Glyph of Unleashed Lightning (new Prime glyph) allows Lightning Bolt to be cast while moving.

Nothing that's interesting really. Elementals lack the ablity to burst as hard as they used to do. Being able to cast on the move, doesn't change anything about it. It's fun for small fights where you can chase someone. In a situation like that, you allready won. I don't see it change a battle in our advantage.