Air Lord, Engineering Corps
It seems the idea behind these guys is to board anything that is normally impossible to board with conventional troops, that's why they have super awesome grappling tools!
But i think they need to be immune to fall damage (or at least need to fall from a greater height). I was experimenting with them and i can already see the annoyance of them hurting themselves from fall damage before they even board a ship or building.
For example just now as of posting this i had them try to board a building from a landship, they did some sky-island parkour and then broke their little legs because they don't slow when they went down from the grappling hooks, they then got into the enemy building and died shortly after.
A boarding party of 24 should not have been destroyed by a building of 8 normal sailors, and i think fall damage may be to blame. (they seem to instantly down each other anyways, so i may have just been super unlucky)
Another thing to note is that it is REALLY bothersome when you board an enemy constructable and can't get your crew back out because there is no bridge.
This is also the best way right now to completely stop boarding enemies in their tracks because once they get into a bridge-less ship they become useless, a good way to cheat boarding AI is to just make a brick that is mostly ammo stores and minimal crew, and then bomb your own ship once the enemy takes it over..
Hm, so this is an issue with boarding from landships, really. Do they do the thing where they want to grappling hook swing, but then the arc propels them to smash into the ground?
Also note that they are weaker than air marines, and a lot weaker than grenadiers.
Also, good point, you should be able to move troops out of not-under-command ships.
They want to move to a sky island or another airship, realize it is faster to do something else half way through and cancel, which drops them and kills/severely hurts them.
They need to either fully commit to every grapple or have multiple grapples to change direction mid air (think Terraria's Ivy Whip item, a grappling hook with three different ends).
They almost 100% fall down on tall buildings from floating islands nearby, they go up on the island and then drop really hard before trying to climb back up the building.