The mage talent trees need a rework. It's playable but it's far from being in a great place compared to the privilege the class has always held over the years in wow.

There are changes coming in the next major patch, but it doesn't change the design of the class/spec really which is where the problem currently is.

For your first character in this game, mage would be fun to level up, but if you're not a total newbie and get a grasp of the game well at Max level and get into the endgame, there is a high possibility that you might have some regret and reroll.

This is my own opinion that comes from playing every dps spec in its current form at endgame and it is probably one a lot of players share, but there will be plenty of those that will go against it. I'd suggest you give it a shot. I personally found mage to be extremely lackluster compared to everything else I've played.