Most low apm dps class and why ?

[Stepjam]

Good choice! It has slightly more actions per minute than a black mage but is easier to play well.

Now, if the melee bug bites you, I'd suggest monk. I suffer from fibromyalgia, which causes pain and difficulty in concentration, and I have found monk easier the dragoon. Although, I have to say, dragoon is more enjoyable.

I'm pretty sure monk has the fastest GCD in the game with the 4th GL stack. It's still less busy than NIN because less oGCDs and no mudras, but yeah.