At least I'm not the only one. I myself am in need of alternate crew and marines since I usually play as an alien in power armor or as a mutant humanoid in power armor (think Warhammer 40K's space marines mixed with elements from the original old-school X-Com's Muton alien) or as a living machine in some rarer cases.
Neither of three use humans as crew or marines since too much sentient life forms can ruin the unknown Pilot-Captain's sense of home, solace, peace and voluntary sought after isolation to gather thoughts and plan things. Means that only fool-proof robust but high-tech robots, drones, probes and computer systems are allowed only and all of the above is replaced with default crew to act as monitoring units, repair units, sentry units, patrol units and basically as all-around versatile units meant to only follow one living super-entity to hell and back and then some.
For the time being though. I just fly one of the super-ships in my collection that have insane amount of space for cargo, fuel, crew and marines, the latter two which I treat as cargo because of play-pretend that it's actually my far superior but robust machines doing all the larger work around larger area from surveys to invasions exterminatus-ing, missile-bombarding the foe in multirole shuttle-crafts while I am in my main ship which is usally large but still a fast flying terror over cities, raining down heavy missile-bombardment to using other desolating weaponry. If I felt like razing something completely beyond repair like Templar and Luddic-anything worlds, I think/play pretend/imagine of sending down a large swath of much heavier nuclear fire.
Any religious in-game factions is always the first to receive such a cruel treatment from me and so my next targets are usually always corporations like Tri-Tachyon, dictatorships like Sindrian Diktat and also whatever the heck Persean League and Hegemony is. So meh, I play this game sometimes for getting rid of my dark impulses of vast destruction and drain myself free from rage enough to keep myself healthy and sane.