I've seen it asked a few times as well, but we have a rule on this forum that you don't ask others to make decisions for you, and if you post some idea, then back it up with numbers. If you like you can present us with some calculations showing the dps difference between 1% crit and 1% hit then fine, please share. However, what you are actually doing is just being lazy and asking someone else to tell you.
I have seen the question of Best Alliance Mage Class asked more than a few times, so I shall answer this as follows...
Although the idea of "Best" could be up for debate, through my experience the Ideal allliance raiding class for a Mage is Worgen. The 1% increased Critical Strike chance has it's obvious advantages for a raiding mage.
Some would argue that a Draenei may be a bit better, but there is more than enough +Hit gear available to meet the requirements needed.