If you checked out the falling stars talent, that is pretty much exactly what it is except on a 15s CD instead of 8. Also we already have an "arcaney" use for fire blast, when you have no IF charges and have to move you should be casting Barrage, Fire blast, Ice Lance in that priority. Fire blast, while not optimal, is a great movement tool for those pinch moments when you are running a long distance. People seem really hung up on the idea that every spell needs to have it's own version for every spec, and while it works for some specs taking fire blast and turning it into a rotational ability for arcane would take away from the spec more than add to it, taking away a situationally used spell. Situational spells are important to the game, you may only use them a few times a tier, maybe on a few fights, but the fact that you have them and used them means they have that value. It's like our 45 talents, they seem useless until they are extremely strong, you want them turned into something else until you realize how you can use them to deal with certain tough to deal with mechanics.
I really see where you are coming from with this, but it will hurt the class to take away a fairly useful (and quite short) movement CD just to add to an already smooth rotation.