in the next patch, arcane is getting fixed i believe... idk how well, but we'll see.
arcane blast is getting revamped to not sucks, but also in a way so its ab spam till your at 20% mana, then use frostbolt to recover mana (like in 2.4).
from what it looks like, its going to be abx3 then arcane birrage/repeat. use fireball when pom is up. seeing that totw will work with ab, i think it will be respectable damage. assuming the talent tree itself don't change, a heavy arcane (something like 68 points) will provide with very high unility/mobility/survivability, while providing good dps. i don't htink mana will be an issue, because, well, the amount of mana regen in an arcane build is very very big. i think arcane mana regen, with appropriate gear, can be the highest in the game bar none.
i'll update when i have more info