I love this thread, yeah I know it's aging.
Q-"Which is the easiest & very less button press DPS job there is?"
Forum Responses-- Dancer, Bard, Red Mage, Machinist, Summoner, Scholar, Black Mage, White Mage, Dragoon and Honorable mention Monk.
Majority votes...DANCER.
If I am correct that means only Ninja, Samurai, and Blue Mage are eliminated as possibilities.
And there are those who will tell you Blue Mage is not even a real job.
OP I hope that narrows it down for you.Good luck.