I've definitely heard from other more experienced players that the game can get a little boring after a few months, and players are locked in with huge armies. Here's my idea. Add a fixed time limit to every server and make it a pretty long time limit. Make the last 10 days (maybe more, or maybe less) an armageddon period. The key point of this period is that troop maximums are removed so that players can send massive armies against each other.

Additionally, remove the use of truces (maybe city teleporters as well). The goal is to create massive destruction in the final days of the server. Add a hall of fame where the top 10 players in ranking are recorded. This encourages players to attack each other and particularly higher level players to climb up into the hall of fame. Additionally add a hall of fame for alliances as well so that there is an incentive for massive battles.

Another variation of this theme is to have alliances be capable of triggering armageddon. Have an extra building (silly name example: temple of doom) that requires a LOT of resources to build. When an alliance builds enough, armageddon is triggered. Other players can abort it by taking the cities with the temples (make the building destroyed upon city capture).

Again record alliances that successfully build and hold the temples in a hall of fame.

This might help alleviate the stagnation of some servers, but it also might be painful to have to restart. Maybe have some carryover into the server reset? Bring a hero along maybe?