You kinda ruled out all the dps classes.

Bounty hunter would be good but they do a lot of aoe and their single target fights are kust the same three button situation you said has you bored.

Melee dps has some drawbacks. A lot of bosses do knockback followed by snare which sucks a lot more for melee than ranged.

I tank as a jugg and i like to see melee dps in the group. There are a lot of opportunities for offtanking adds and assassin/maurader/ powertech dps do this really well. They can lock down a group of normal strength mobs without dieing and thats one less thing i have to worry about as a tank.