I'm interested. Is it too late to join in?

Edit: A good reason for the massive teams is quite simply a lack of experienced manpower; There are only so many higher ranked shinobi left after the war able to train Genin to be useful for things more then meat shields (or at least train them to be decent meat shields) and thus those few that remain need to teach more idiot kids to make up the difference. 

Not ideal, but life is tough.