I'm fond of the mentoring system used in EQ2. The higher level characters mentor down with an experience penalty. But the lower leveled characters acquire a slight boost in adventure experience. Are Sidekicks the Champions Online variation on this theme?
Either way, I think a mentoring system of some kind would be fun. I would suggest calling them a Training Cruise Mission. Higher ranked officers taking time to boost the skills of those from the lower-decks. IMO, it seems a logical fit with the environment.
I think that is a great idea btw.
To OP - what everyone is saying on here is correct. More enemies and tougher enemies will spawn based on the group size. I do not believe level has much to do with this, but I could be wrong. Me and my roomy tested this last night - I was a Lt and he Lt Cmdr. We went into a sector patrol mission together and the groups of enemies were either Battle Cruiser and an Escort or an Escort and 3 BoP's. Then we backed out, I dropped the quest and got it again to start over fresh, and left the group. Going back in it was either a Battle Cruiser or 3 BoP's. The levels on the ships themselves were a little lower as well.
A couple nights before that, other friends invited me to a group with a newbie friend of their's. I almost cried for this guy. They were Lt 8 and Lt Cmdr 9 respectively. I was Lt 5 with this character. The newbie was trying to do his missions while the other two were just in sector space deciding on which Lt Cmdr Fleet Action we should all go try (shaking head just thinking about it). I immediately notied the newest guy was in the very first Vulcan sector patrol mission and getting kicked around bad. I raced in to help him and found a Lvl 3 Lt taking on 2 +5 Battleships and 6 +2 Frigates - by himself. Once the others showed up, the finished those ships off easily for us because the ships themselves did not seem calibrated for their level but rather for the group size.