This is a horrible deal for the Pistons, I can't imagine what Joe Dumars could possibly be thinking with this. AI is a gifted athlete and scorer but he is not a franchise player. He can't run a team like Billups, he can't be a leader. In fact, his attitude and selfishness with the ball tends to make him the exact opposite of a leader. He can score a lot but he needs a lot of shots to get those points. Billups is an efficient leader who distributes the ball, knows when to take the shot, and can nail the 3. AI is a washed up ball hog on the downside of his career.
Not to mention you also lose McDyess in this deal, who is a solid low-post scorer and rebounder.
I agree with everything you said in your post.
One article I read quoted Dumars I think saying he made the deal because the Pistons have lost in the Eastern Conference Finals for 3 consecutive seasons. They lost to eventual NBA champions Miami and Boston 2 of those 3 seasons. Detriot ain't gonna win an NBA championship with Mr. Practice!