Some thoughts on assault shuttles.
Since they are small craft, should they not need to have a reload cooldown similar to fighters and bombers (get to target, return, refuel/rearm)? So since they are speed 8, the only way they could launch and retrieve in 1 turn would be if the target was at range 4 or less? And then they would still need 1 turn to refuel.
And should they not have a designated capacity? Right now its overall crew, but shouldn't it be just what is loaded in the assault shuttle bays? A doom star (1350 base crew) and 1 assault shuttle bay (+ 50 crew) should NOT be able to deploy 700 troops from that one bay. On the other side of it a human carrier (100 base crew) with 2 assault shuttles loaded with space marines (+200) should be deploying the full marine compliment of 200 not 150 as current. Perhaps a locked boarding compliment exclusive of ship crew for assault shuttles (what comes with the shuttles goes with the shuttles, lose it and you don't get more until you are able to resupply).
Boarding module and Transporters are direct point to point contact accessing 1/2 available crew, assault shuttles not so much...