I have an idea to make this gratuitous, Leech pods. Like what Hydro suggested, little pods that latch onto an enemy ship but the pods drain the energy from the ship and return to the ship it was deployed from giving the ship power.
but once the battle starts, it doesn’t matter if the power is taken away. it has no benefit to leech power and steal it for yourself mid-battle
This would be the only sort of “boarding” action I could see working within the way GSB works. Basically a weapon like any other, only instead of firing a missile full of explosives, you’re firing a missile with saboteurs inside. If it makes it through the shields and hits the ship, it bypasses the armor and deals some damage to a module within, before the saboteurs are overcome and gratuitously dismembered and spaced. There could be two versions - the regular Saboteur Pod and the Droid Saboteur Pod. Really really slow rate of fire, but fires two or three pods at the same time. Droids would fire faster because you don’t have to get them drunk in order to coax them into the drop pod. 
I just got the mental image of C-3PO sitting in a boarding pod with a load of super battle droids… xD
Actually I don’t worry so much about the game handling it; my concern with captures would be more of a scoring issue. When I capture a ship, the enemy’s % remaining should drop, because they have lost a ship, correct? Then does my percent go up as well? Does the captured ship act as a buffer for the 10% loss threshold?
Not that winning a round with none of your own ships surviving and a bunch of captured enemy ships now comprising your fleet wouldn’t have its gratuitous appeal.
One question: how do you show a boarding in effect? (maybe people being chucked out of airlocks xD!)
Probably as one explosion at the point of drop pod impact, followed by a bunch of little ones right in that area. (For saboteurs anyway.)
I still like the idea of chucking people out of airlocks!
I have no idea what thread I stuck it in, so I’ll just mention a “weapon” I threw out somewhere else here in Suggestions: the Mutineer Gun. Don’t remember the context, but it was basically a weaponized concept of spacing people.
There you go.
You got stuck in a thread about boarding parties and how to show boarding in effect
But I’m fairly sure I didn’t require the mutineers to be drunk at the time, so that’s a change from most of my boarding threads. Also, it’s a pretty good idea.
how about a gun that fires crack cocaine? Get the crews high so they can’t do anything?