Thanks for your suggestions
Save/load missions: Indeed a feature, that has been requested quite a few times already. I'll see, if I can come up with a reliable solution to do that.
Item descriptions: I actually got this already working in an experimental tool I never released to the public. However it depends on the mod authors to correctly name their ship classes and devices and supply the game (and the Skirmisher) with all this information. Not even the original game does this for every piece of equipment, so I don't know right now, if every mod cares about these details. Some classes or devices would be left without description or a proper name, I guess.
Ingame fleet configuration: As far as I know, the fleet configuration screen isn't available in single missions. It's only being used in campaign mode (and multiplayer), which isn't really available to your average mod out of the box. Even if it was - the Skirmisher just isn't meant to create campaign missions, so it wouldn't even work that way. I could try emulating this behaviour (or even the interface), though.