For the AI tourny. Do they take forever cause of sand bag?
Sprite limit.
If they were 5 v 5, there would be the potential of 10 different sprites on screen at once. The game can only draw 9 before it begins to wig out, and 9 is an odd number, so 8 is as high as you can go. You could do a 3 v 3 v 3 AI tourney, though, that could be interesting.
If we made it 5v5, we would have to impose more restrictions. Something like "Two units must be the same base class" or something. Which honestly sounds stupid, and then there will be about 100 topics asking why there is this random rule =p
As for 3v3v3, I have considered it Raven, and actually tried a map once. What happened was that 2 teams would go for 1 each time. Unless you had a perfect triangular setup, one team would be screwed. I tried swapping the teams around as well, the team in the bad position just always got 6v3'ed. Or maybe it was my bad map placement.