Now that I have a TV at work, I've seen a little more summer league than I usually do. I think it is a real waste of time mainly because all you have to do is the math to see that at least 80% of the players will not be on a roster come the season opener because there just aren't enough slots. So what is the point of having all these non-NBA players playing in this development summer league?
My better idea is that what you do is create a summer program where each team can send their draft choices from the most recent draft, up to 2 players from the team's D-League team and up to 5 players from their regular roster with restrictions on playing time/number of starts so that those 5 players are basically the bench players that need the development. Notice that I'm saying "up to" in each case, a team wouldn't be required to send any players.
Then what you do is take all the players that show up and place them on teams in a random sort of way according to position. Have coaches from outside the NBA do the coaching to prevent teams from loading up. Then have those teams play games and practice at a rate of about one practice and one game per day or every other day. Then after a week or so, reshuffle the teams and do it again.
I think this gets the draftees and D-league guys a chance to play against actual NBA caliber players. It gets the bench guys a chance to play against each other. It gets the players used to the idea that the guy you're playing hard against now might be on your team later. It just doesn't matter who wins in the summer league as it is contructed and it isn't coached to win; after all the Nuggets had a perfect record in summer league one year being coached by Jeff Bzdelik and that season was one of the Nuggets worst. This way is a way of admitting that it doesn't matter who wins. You might try to create some incentive by saying that losers have to run stairs but it doesn't matter. These guys will be playing for their professional lives but not having to deal with the guys who are totally desperate to make an impression in summer league as it is now. I think that the people who show up now for summer league will still show up for the games that I'm talking about. You'd just have to do a better job of publicizing when each player will be playing.