Not that it'd really matter but with zero crit rating you'd still have at least 50% crit if you consider in your crit from int and talents.
Assuming 50% crit on a frozen target and 20% crit damage reduction, you'd on average do (including CSD):
0.5+0.5*2.09*0.8=1.336 times the damage of a noncrit FB
An additional 327.9 Crit Rating (=7.41% crit) would increase that to:
0.429+0.571*2.09*0.8=1.384 times the damage of a noncrit FB
This results in an increase of:
For the same budget you could also get 10% haste.
So, would you rather have 10% haste or an additional average 3.6% damage on your shatters?
For every crit rating you drop your burst becomes more and more unreliable, it's just stupid when I yell "SHATTER" on vent and I get a 3.5k frostbolt 2k icelance noncrit... It's like that half of the times when I shatter on a KS. And the target stays alive.
Sure I love all the haste I got, it's nice for getting polys out and turreting frostbolts. But I still kinda miss the times when my shatter was almost guaranteed to crit.
Yes, haste is more useful than crit overall, no doubt - but I wish there was a way of getting "enough" of both stats since mages do need both.