It would be a great feature to have mission stats on your Kerbals. And as they gain experience they gain the ability to overcome mechanical issues. (that is, of course, if random mechanical issues are part of the game in later versions). Also, if a new Kerbal flys a mission with an experienced Kerbal, they might get a bit more experience than they would with a totally "green" crew. (note, the "green pun",,, arr arr). Maybe even a rank, Kadet, Kommander, ect.