After one level of Freespace 2's main campaign where I completed all my objectives, I was told that I had "flown an excellent mission" when I clicked on the Recommendations button. However, on other levels even when I complete all the objectives successfully I'm simply told that there are "no recommendations for me". How do I earn this praise? Will this affect the dialogue I read post-mission and/or the missions I play?
The "recommendations" expansion in the debriefing is just something that is put in via the FRED2 editor, and most official campaign missions skip recommendations if you completed the mission properly.
Sometimes, when the mission isn't clear if you succeeded or not (e.g. a friendly ship blew up but there is nothing you can do about it), then it will tell you that you "did good" and that the mission was successful.
If all primary objectives are complete then you pass the mission, secondary objectives and bonus objectives just give you more score/medals, but the recommendation pull down isn't tied to the objective system.