Even with the interact with target (which your going to want just for the ease of interacting with NPCs and perhaps looting mobs) your going to want that 'wiggle' to be something you have mastered. So you likely turn the mob a bit with the tank and let the melee dps get a flank on the mob, this you will end up doing most of the time it seems (and praying your guys dont randomly decide to interact with unaggroed mobs ... dont spam interact with target if not needed)

The trick with melee I think is to be able to rapidly perform turn overs from one mob to another. Where in a tank+caster situation the turn over is easy since during the casting of spells you would be able to switch targets and not have idle time.

I found it useful to do this on the PTR or as deathknights a bit to get a feel for it, because low level characters just don't work the same higher level characters (a whole lot of missing and being dodged). Then go back to the low level characters, just like low level casters. I found it was just easier to do mundane sequences (heroic/sinister) versus trying to play like a solo player and actually do the finishing move.

I also found overkill or resource waste to be a problem, I don't know how to resolve it really. It happens with casters as well, but melee characters seem to have a lot more fight expenditures to manage (combo points, rune sets, rage). So where a caster might have a mob that is going to die from one caster's spell, you still toss 4 at it.

For your warrior + rogue group, you likely want to have the combo points visible in some fashion just like a dk would or have parrot setup to spam under a unit frame that your at 4 combo points or whatever.