Another idea about the map changing (sorry, im a bit involved on this matter
...)
If after every war there would be a map changing, with several different scenarios, the war will be far more interesting.
Even it would be funny having some of them (no many) cohoperative scenarios, in which both sides must cohoperate or the world would be destroyed by a very aggressive underworld swarm of something evil and cruel, which leads to a temporary alliance between factions. One scenario like this every 5-6 wars should be interesting.
And, some smaller map with a very challenging war with some special features, when one side is too strong also would help. I, as Klaas, like the strategy more than tactic, and more different scenarios will increase a lot the fun
Also, the pvp could be used to special hexes, idk, where u can take it only by it. For example, a narrow path like the Termopili for the spartans, or a dungeon hex which block a secondary path toward the enemy capital and so on.
I strongly believe that the scenarios will help a lot to resolve the unbalancing.
Lot of work for the devs, but lot of fun for veteran (and new) players
and more active players, and more new players...