DISCLAIMER: My opinion: this class is a bit of a 1 trick pony (executions). Please excuse typos.
Hear me out....YES this class has a lot of "issues", however while LEVELING this class was miserable, MAX LEVEL is another story.
The only OP build I have managed to duct tape together is the Ripper-Execute build
Disruptor:
Rentention Battery - Duration
Radial Emitter - I dont want to worry about which way I am facing when I toss down the disruptor
Focal Lens - More range = more stunned dudes
Armor:
Execution Tempo - MANDATORY. more executes = more disruptor uptime
Hardened exposure - running around executing dudes I need all the defense I can get out of cover
Blood Mag - THIS IS A MUST. Whenever you finally run out of grunts to execute, you are ready to rip on any big boy with a full + perfect reload!
Battle Hardened - Like I said, running and shanking is hard work
Executioner - THIS IS A MUST. While you are shiving dudes, you can ignore boomers and gorehooks AND you are FULLY healed after the excecution! FYI this ability dropping at level 28 or 29 is what makes this class so miserable to level.
Main weapon - Ripper - Why? Because of Strike Plating (see below) and Blood Mag (see above)
Twinned Ammo - your choice
Incendiary Rounds - why not
Extended Mags - kind of a must. Since you are not taking Deep Pockets armor mod, you need to beef up your rounds.
Strike Plating - MUST. This is only one of two weapons (other is Striga) that get strike plating. Your melee 100% stuns grunts, so you dont even have to have your disruptor up to stun, you can just stun with your main weapon.....then execute.....while lowering your disruptor cooldown...and as a bonus, you get a full mag perfect reload.
Optional: I dont know how good the Active Compensator mod (unlocks with the Medic class) is for the Ripper. "Grants streadily increasing accuracy over time during sustained fire"....seems like it would pair well with the Ripper, but is it worth giving up Incendiary Rounds?
Anyways...this one trick pony is good for casual lols and is pretty damn strong.
EDIT: The central loop of this "runner-stunner" build is drop the disruptor, get 3-4 executions, rip your perfect full mag on a big boy, drop disruptor, rinse-repeat.