I have a suggestion that might make boarding actions work better and more tactically interesting.
Make crewmembers, and maybe guards, a little tougher at fighting, maybe 20%. After all, they are fighting defensively.
Add a surrender value (%). This would be equal to 1.0 times the total % damage the ship has taken (or maybe 1.5x or 2.0x that percentage).
The instant a crewmember is engaged in melee combat, it makes a surrender roll to see if it immediately surrenders without a fight.
The net result will be that it is harder to board an undamaged ship (good functioning, high morale) and easier to board a ship that has been softened up.
Maybe guards do not make a surrender roll, or maybe guards surrender value is halved. I speculate that you can probably reduce the number of guards per module using this system.
An unexpected side effect will be to make spiders relatively less powerful, as crew do not surrender against them!
Spiders weren't engineered with a surrender option. lol
boarders should have a surrender role as well. depending on troop type and current boarding force. A solo boarder boarding a flagship will be almost 100% surrender chance while a proper crew boarding a small ship will have a very low surrender roll %.