Both root you to the spot, only meteor strike should be cancelled when flinched.
If you make it so that movement is enabled, but the spell is cancelled as soon as you move. Then you are not changing the situation, only making it easier for wizards to avoid melee classes.
As I see it, there are 3 problems:
1) Meteor strike can be cast even when you are flinched.
2) The time between finishing blizzard/meteor strike and casting a new spell such as flamefield, is a shorter time span than between two regular spells, due to the delay on how long these spells take to cast, so essentially the damage comes in two blows very rapidly.
3) As with most spells, when you cast blizzard/meteor strike on a moving target, the spell is not cast upon the square that the player was in when the button was pressed, it moves with the player for a short time until the spell begins to proc.