I also want to say another annoying thing about fortress mode is the voice. Every 5 seconds, the announcer will say 'the forces of dark is under attack' or something like that. then 5 seconds later it will say 'the forces of light is under attack'.
The reason for this is the fortresses throws out a rock at the other fortress once they are upgraded. So you get the annoying announcer nonstop making announcments of both teams under attack. The announcer should only make an announcment if it was a demigod that attacks the buildings. Not minions, not rocks. Or make it an option.