I feel like folks are sleepin' on skirmishers.
You don't use them as pure shooters, though they are reasonably competent at that. The fact that no action is turn-ending means they're quite versatile in many disparate situations and can do a pretty good job of jumping from place to place making life hell for the aliens.
You can pull enemies into a vulnerable position with Justice and then reposition the skirmisher using Wrath or Grapple (remember, Grapple is a free action). You can Grapple up to an enemy position, use Justice to pull another enemy in, then move them to another enemy out of the blast radius of the grenade you just set up the enemy force to get hit by, while also shutting down that third enemy with Retribution (which is just Bladestorm by another name).
And, of course, it's always nice to be able to grapple up to a decent shooting position to get that height bonus, though that's not something unique to skirmishers - still, they require no extra investment to get that ability, so that's nice. That on top of being able to shoot twice at the start (granted, with SMG-level damage, but still) makes them a pretty consistent mainstay in my latest campaign. It's great to be able to ever-so-slightly mitigate RNG with more chances to roll. They also have a pretty good Overwatch tree, but admittedly, I really don't like relying on Overwatch, so the only one that ever saw use during my last campaign was Battlelord (which lets you use any action after any enemy action).
They're not flashy, but they're versatile and fun to use. And damn, I love their aesthetic so much! They've got some of the best armor graphics in the game. Wish I could stick that armor on all my soldiers.