True, but how much better if those same traits had been worked into the characters during a creation session where you have invested time and thought into building your character. You can then have one-to-one sessions during that process for the DM to introduce the links or additional background. Also the players then help to form those relationships which can often be better roleplayed because they have taken part in the process rather than read a cheat sheet..
There is good argument for both but on balance I prefer the creation process because then everyone has much more of a buy in to the story and backgrounds that way. Though not all people or systems enable that to be easy. The other benefit is again it helps people understand the system better as character creation makes you work though a lot of things so you get much more familiar with how they all interact.
Nine times out of ten, I agree with you on this. For most games, I increasingly suspect the more player involvement the better and I've been toying with front-loading a lot of that and getting players in right at setting creation effectively, stealing shamelessly from the Vampire the Requiem 2nd edition "Building the Ladder" thingy.
But there's always the corner cases, and there's definitely room in the bag of tricks for the precise method of the B5 game, especially when uncertainty and paranoia are sought after.
Hopefully, I'll soon get to try out the Vampire system in live play sometime soon, after a hell of a long build-up. Just got to put the at this point quite long-running Cyberpunk game to bed first. Should be a real hoot, as my players will be not only digging into their own character, psychology and backstory but also building a significant chunk of a New England/Maine town or city and the likely very complex web of NPC's that will make it up.