and what happen if you can't get your automatic scrimmage?
Virtually impossible. I mean, sure, if you have 713 teams request scrimmages, then 712 would get them and 1 would be left out. Which means they would have to arrange one themselves--which puts them no worse off than the situation as it stands now.
If you wanted, you could put the deadline for requesting an auto-scrimmage at, say, Monday midnight instead. That way, for that odd team that doesn't get one, they still have a couple days advance notice.
Or heck, even better, in situations when there happens to be an odd number of teams who requested scrimmages, then the computer could automatically assign one of the CPU-controlled teams to play that last remaining human team.
It really isn't a huge thing to add, I don't think. I play an online football sim game, and in that one the game automatically assigns a set number of scrimmage games to all teams (some during the preseason, some at the end of the season for teams that don't make the playoffs, so they play the same # of games as playoff teams do, etc.) And then, if a team owner wants to schedule *additional* scrimmages as well (for example, to test out different lineups or play around with changes in formations, tactics, etc.), he can do that--though there is no experience "bonus" given for those games, they are purely for testing strategies, not for additional player development. Some owners take advantage of the opportunity and schedule tons of scrimmages to test out all sorts of different things, other owners don't schedule any all season and just play with the "set" scrimmages assigned to them by the game. Seems to work out well.