1. Made fortress no longer territory root, meaning territory will decay if the cc next to the fortress is smashed.
Reason:
Players in TG build a fortress next to their cc when expanding. If the cc is destroyed, it doesn't matter because the fortress will always hold their expansion. Now, we have to destroy the fortress as well to deny the expansion, however, the total health of a cc and a fortress is 3300+5200 = 8500 (for a default civ), which is much higher than just a cc. Many more siege weapons will be needed to commit to destruction, which leads to stalemate and less interesting gameplay. The civic centre becomes useless in late game and players often don't care if their cc is under attack.
Furthermore, fortresses are especially cheap in A24. Stone is no longer used as much (only in barracks and phasing up), so it is very easy to spam out fortresses. Eventually it becomes a game of who can build the most number of fortresses and turtle for the longest.