Mmmm, I guess auto-attack would be best.
A clicked attack can get tiresome if the RPG features a lot of combat. BTW to add some flavor to simple combat, maybe you can add something like fighting stance.
I mean giving the player the option to auto-attack in a defensive, balanced or ofensive fashion. You may even variate the attack animations for each stance.
Stance give diferent stat bonuses, like more parry rate or critic, etc.