Doesn't seem to be so "evil". His manner of speech would suggest that he is "honorable". That he may have been forced to ally with Deathwing, and perhaps he allows the heroes to "defeat" him. The Eye of the Storm mechanic seems to support this, that he is testing their strength...
It is said that the weapon he wields might be the legendary caster weapon that has been of much discuss, in the form of a dagger perhaps...
To me it seems that Al'Akir is not done, and that he will play a role in the future, that role nobody knows. I like Al'Akir and to see him simply disappear after being defeated would be a waste.