I suppose if you look at it in the wrong light that it is pointless. Sure if the defense and most players, top to bottom, just plain aren't very good or don't have pride in earning or keeping their blackshirt then it is rather pointless either way. My problem with the current system is it merely provides a distraction and appears to be a negative or non motivator for the players. There is no benefit to the team if an under performing defense is concerned about when they are going to get their blackshirts. Picking some relatively better than average performance in the middle or later part of the season simply has not worked to any positive effect. Look at knapps summary of when Bo has handed them out, why, and then the D's performance after that.
My opinion is that it is a useless window dressing tradition if it does not motivate the players and help make the whole unit better. Bo's way has not accomplished those goals. If you are the best performing player at your position, you have earned it whether you are very good or not. If you stumble one week and it goes to #2 on the depth chart, hopefully it would motivate both players, one to get it back and one to keep it and possibly 3 or 4 to step up their game and go after it. If nobody has them, you don't have that.
The other problem I see, that nobody has brought up, is that the current system seems to put all responsibility on the players and zero on the coaching staff. The gist is, we coaches have these to hand out but you guys haven't done enough to earn them. It kind of glosses over that possibly the coaches aren't getting their job done too and puts it all on the players. If they give them out for the first game, they then have to admit that this is the best we've got to offer and, if it's not real impressive, then that's on the coaches as well. It helps to hold them accountable for their recruiting and what they're accomplishing in practices.
My only dog in the fight, besides the obvious desire for a more sound defense, is that I don't want to see the tradition watered down to having no meaning. Giving them out in week 8 and getting your ass handed to you in week 9 and the CCG tarnishes the tradition way more than giving them out week one and then going about your business with the constant motivation of keeping that shirt or getting it from the next guy.