I think the Devs once mentioned that it was an explicit design decision that the world population decreases much easier, so that the world is depopulated at the end of the Ascension war.
Hence one could think that this encourages players to win a quick war before their resources are all spend. However, since money and resources become more and more unimportant as the game progresses and magic resources and need-not-eat-nor-upkeep creatures become more and more available, the situation is quite the opposite, encouraging delay.
Maybe some ritual spells should consume gold or resources as well. Hmm, or maybe the maximum dominion strength should be tied to the population size. The effectiveness of ritual spells could also be tied to dominion strength, hence encouraging to speed up before all lands are laid to waste forever... (proposals for Ermorian Dominion in this setting?)
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BTW: we finished a 7-player game on inland with the victory condition graph as outlined by me in your pentagram-thread (cited in the second post). It was a fast and violent game and very funny in my taste, although it was prematurely ended by another player sending his Caelian flyers grapping a couple of victory points, which we had as an alternate victory condition...
Funnily, my friends either really liked the game for its speed or heavily disapproved the style because it prevented build-up/hoarding strategies...