Glyph of Frozen Fortitude - Major Glyph
Modifies your Ring of Frost, Ice Ward, and Frostjaw to become defensive abilities, rather than control ones. However, it also increases the cooldowns of all three abilities to 2 minutes.
Ring of Frost - 2m cooldown
Summons a ring of frost that reduces the damage taken by party and raid members standing in it by X% [20%] for Y seconds [~8s].
Ice Ward - 2m cooldown
Places a frozen ward on the caster's target that reduces their damage taken by X% [30%] for Y seconds [~10s]. In addition, the target cannot be affected by snares, roots, or knockbacks while protected, but said affects can still be applied to the target.
Frostjaw - 2m cooldown
Freezes the target's jaw, invoking intense pain that breaks their concentration, causing them to deal X% less damage [-25%] for Y seconds [~4s] or the next Z attacks  (whichever comes first, Y seconds or Z attacks).
(Stuff in "[ ]" is just what I feel the variables should be)
So how's that for some defensive abilities? Gives us the choice between a raid cooldown, an external cooldown, or a unique ability that reduces a boss's damage from a specific mechanic!
Turns our useless Tier 3 into an amazing choice! No instant go-to talent and gives us a variety of defensive cooldowns that are all extremely helpful in tons of scenarios. Sure, one of them will be better on specific fights, but that's the point about talents, right?
In addition to that, it also gives us another choice for major glyphs (a near mandatory one, but a choice nonetheless), something that Mages are SEVERELY lacking in (in addition to raid utility)
(If anyone likes this enough to want it to come true, feel free to post it on official forums. I would, but... well... let's just say I don't have posting privs )
Edit: I like how I came up with these on the spot, but damn, giving it some time, I really like what I came up with