Here's one idea: On the part where you fight in orbit of the planet, instead of fighting 3 separate groups, how about fighting them all together, but with some more orbital platforms to provide support. The situation could be that there is a large group in orbit of the planet, which is clearly too large for you to handle yourself, but there are orbital platforms that are offline. The player would have to power the orbital platforms up in order to help him defeat the orbital force (there could be a nebula or something to explain how you can get close to the platforms without being detected). If you wanted you could even have a dialogue based puzzle to power them up.
Thanks for the detailed review. I like your idea about making the space maps a little more interesting. I don't think I'm going to go back and alter the mission as it stands now, but it could be a good idea for part of a future mission.
While I agree that fighting 3/3 enemies can get tiresome and tends to make up the bulk of space combat missions already in the game, I felt like if I didn't have some element of that in there I would have gotten reviews slamming me for not having enough combat.
This mission taught me something important about game design: it's impossible to make everyone happy. I was reading one of my mission's reviews and the reviewer essentially said "combat was too hard" and the review immediately following it said "combat was way too easy." Those contrasting opinions sum it up perfectly. I've gained a new respect for what the DEVS do, that's for sure.