@chris0707070707 Well, I'm an end game player with a good seed production, so I should be able to upgrade all buildings within one month after finishing the chapter.
But when Embassies is no longer last chapter, there will be players with low wonder levels who finish the chapter and go directly to the next with some buildings still unupgraded from Elvenar's chapter due to lack of seeds (and having 20 seed/cult hybrids won't solve the lack of seeds if the hybrid's production rises so small in the next chapter also).
Don't forget that seeds are still needed to create expired goods and with researches each in hundreds of thousands it takes a lot of seeds to accumulate that numbers and not everyone has a level 30+ Simia for 2% decay (most of those players will have decay 8-10%).
And 2 milion mana can be a problem for a lot of less active players (we who play tournament for 10k+ points have almost unlimited mana in our inventories, but there are many players who do few hundreds points max and without a large mana hybrids pool these amounts might be just at the edge of their decay max mana limit - just saying that even mana can be hassle for some players)