With a combo of arc thrower stun + stasis from a psi-op, I was able to take down berserker king on the first encounter without taking any damage, with a team that didn't have very high damage output (half of them were carrying laser smgs.)
Also, unrelated note: R.A.G.E. suit on a ranger is awesome. Punch charge followed up by sawed-off shotgun blast. So satisfying.
Assaults have really gone out of style for me after my most recent playthrough. Pulling extra mobs feels so bad. I do use one assault consistently on network tower offenses because of the huge damage output from close encounters. I mean they're quite excellent, easily one of the best, if you KNOW there aren't any mobs you will pull afterwards, but that situation is rare.
Yeah I tend to have an assault on my back-up squad but not primary. They are really awesome if close encounters kicks in, but if not they could better be replaced by a shinobi or ranger. The Arc Thrower is GREAT but yeah giving up a lot of damage.
Assaults can be built as great support units now. Electroshock means every Arc Thrower shot will apply a debuff. It's also the perfect answer to heavy gunners area suppression, you might have 10% chance to stun them, but as soon as you disorient them they loose their suppression. I don't have that many of them and i often regret not having one in any squad doing serious fighting.
You don't necessarily need to spec them as support to take advantage of the stun from arc thrower. I like rapid fire, run and gun, critical hit specialized assaults with armor piercing ammo so they can run up and potentially blast high hp enemies for 18+ damage twice. Then they're invincible to the next shot from untouchable and if you position them right, you can use them as a human mimic beacon. I have a run and gun assault now that got the evasive ability from the AWC so she's also got 100 dodge for when she does have to take a hit. Then if you have something scary like a berserker, archon or alien ruler come along, you can stun it and deal with it at your leisure.
I agree, I'm starting to like support grenadiers at high levels better than sapper grenadiers; 50% to stun on flashbangs is too nice to pass up. It kind of depends on the mission though.