Coming from somebody who frequently farms all the 55 FP's as a Marauder:
Hammer - groupwide stun. Even ranged will be stunned, unless it's a merc with Hydraulic Overdrive or something similar.
Stay far enough could avoid some stun.
Cad - Boss pulls the entire group into the AoE; everybody needs to run out, including ranged. So melee and ranged have the same downtime on that.
Stay behind the box and the boss' pull would not work on you.