Lets say the alliances have an extra robot, one thats not required for a "full field of robots" for a match, then heres a substitution rule. There are four teams on an alliance. After each match the captain team
must sub in the other robot. In 2003 and 2004 you had to do this for you second match, but could play any two robots you wanted in the third match. I'm saying that in
every match there would to be a substitution. The alliance captain chooses who's in and who's out. It doesn't matter if its match three, or match one against a new alliance, you sub every match.
I was also thinking that with every substitution the robot that was just put in stays in, meaning that the three robots that were selected would rotate, with the exception of the captain team. But that might make it a little confusing
and I don't think that would go over well with teams.