I find friends on the Social tab fall into one of three categories in my mind..
1. those I play with regularly, know by name and for whom I would regularly click "join match" on logging in and checking my Social tab (and based on experience do the same to me)
2. new players that joined my crew at some point, did well or were just good fun and I think are worth playing with again
3. other players that were fun to play with in a match, either as crew or fellow captain
The problem is that with too many on the list you lose track of 2 and 3 if you don't play together again quite quickly after you first met, or they risk becoming "who are they?". Those in category 2 will generally look me up again and join me in a match if they added me to their Social tab and have a very good chance of moving to my mental category 1. I have to admit to periodically culling off a few of those who I haven't a clue who they are and they haven't logged into the game for a couple of weeks.
Something as simple as a 1/2/3 star rating system against names on the friends tab would help. Three re-nameable folders, or being able to assign a four-letter tag against a friend's name would be better.
