Jobs that are actually fun.

Arans are indeed quite nice, if we talk about fun as how interesting training is.

Aran's have lot of skills that are used during training:

Overswing(normal att, 2swing, 3swing)
Final Blow
Final Charge
Final Toss (not used so much, at least before Chaos)
Combo Fenrir/Smash
Combo Tempest
Body pressure (I count this as attacking skill, cause it gives u body att)
Whirlwind (after Chaos)
Combo Judgement (after Chaos)
Combat Step

and buffs:

Aegis Shield/Combo Barrier
Smart Knockback
Ice Charge
Drain
Freeze Stand
Maple Warrior
Combo Recharge (after Chaos)

Personally I like how some of those are used with combos of arrow keys. I don't like moving my hand to the other side of keyboard. Combat Step also has different tricks hidden, to take full potential out of it. Then ofc, keeping up the combo makes training bit more interesting (and some bosses challenging).