Kudos to the development team for constantly striving to add new wrinkles to keep the game fresh. The one area that's not been touched has been the fortresses. I think it would be a major improvement if you raised the fortress levels to 30 . keep the safe zone at level 8. Add safe zones at 12, 16, and 24 . This would get the strongest leagues already at level 20 to compete with each other once again. There are currently 100 leagues at level 8 . They would now strive to get to 12 and 16 etc. I leave it up to you to decide if and how much the knowledge should increase along with fortress levels , as well as the reequirements to upgrade to the new fortress levels. 

What do you folks think ?