You know, they get overlooked, but honestly, specialists are enormously powerful. Gremlins only taking one action, and things like healing not ending the turn make them able to deal damage and play defense in one round. Combined with Haywire protocol reliably being able to stun robotic enemies from mid game on and my specialist is pretty ridiculous.
Btw, for every hack success on your specialist, they get +5 hacking (Once more per mission). Combined with the increased hacking from skulljack, and later tier gremlins, it makes hacking very powerful late game. As said, almost always a 100% to disable any robotic enemy, including sectopods. Which makes all mech pods a lot easier.
And for organics they have Capacitor Discharge, which effectively lets you bring one less flash bang (It always applies disorient on organic enemies)...Plus with the last tier gremlin it does 10 damage, in a radius about equal to a grenadier with all the explosive perks. Against robotic enemies it does a shit ton, too. (That is unless you're just breezing with Mimetic beacons heh--I'm only letting myself use one, so disorient is still a massively good debuff.)
Plus if you do medical protocol and medic (And the rest in the hacking tree) you get 4 remote heals per match, that cost one action (So you can do two per turn). I know most people say "just don't get hit", but having the capability to heal people up is still pretty big. (Not to mention their +aid protocol at Gremlin three gives +40 defense, or full cover. It is enormous for when your ranger misses). The final medic skill though, I can't imagine why anyone would pick it when the two lower tier skills give you more than enough healing. I mean yeah there is a lot of AE damage later and being able to get it all in one swoop is nice, but if you're entire squad is getting shit on healing probably won't help.