For the next world it'd be cool if instead of building statues to get realm buffs you would need to expand your realm claim over a new type of local resources. These resources could provide buff points that can only be invested in a a couple of different buffs per resource type, so by generating the world with uneven distribution of these resources we would organically get areas with different comparative advantages and hopefully more trade.
Another side of this would be realms competing for territory control over these resource spots, so hopefully we'd get a bit more meaningful endgame PvP. Especially if there's restrictions on building walls in proximity of these resources.
Of course, this wouldn't work at all with the way realms expand currently, because the first one or two realms to pop up would make claim tendrils all over the map and claim all the resources. A way to limit realm expansion would be needed, and I think a good way to do that would be to make realm authority upkeep grow proportionally to the length of its borders. It should scale slower than a square function to allow for somewhat suboptimal realm shapes, but significantly faster than linearly to enforce fairly compact realms instead of ones with tendrils stretching to all corners of the world. That would also mean that only realms in the general area of a resource spot would be able to compete for its control, which would hopefully provide room for more factions in a developed world.