A lot of people saying "all DPS are easy" clearly haven't read the OP.

On to the topic, DNC IMO would be the easiest for someone with ADD, since it's rotation mostly consists of 1-2 combos with ocassional procs. You can set up "proc reminders" on an auxiliary toolbar and increase it's size, for example:


MCH has a simple rotation but if you have high ping you'll have a hard time double weaveing and take a huge dip on DPS.