It would be great to have a clearer view of what role Learns should play OOW. Should it be a waving-tool or a randoming-growing tool?
There is not much incentive to NOT learn wave a smaller kingdom with current settings it seems. Combined with the the sliding GBP into war, and if you are about 10% bigger or more kingdom-wise, it will be difficult for the waved kingdom to make a significant use of a surprise declare and punish the 0 incoming acres. If you are big enough you will still probably be in a good position.
Even more so, there is more incentive for you to learn wave a smaller kingdom if you are 24-25 provs, and they 22 or less. It will mean that you have 2-3 more provs in the same NW (if you are about 10% bigger), which gives you perfect gains, not even bottom-feeding protection from NW-diff in prov-size.
This may seem to cater mostly to top dawg kingdoms, or just in general, bigger kingdoms hitting significntly smaller kingdoms (10%+ smaller).
An assumption is that this is something that generally is worked towards reducing in terms of setting-changes. In current ages I am not sure, but certainly in general in past years.
I am not sure how to go around this. You cant really restrict kingdom-nw-diff gains much more.. hitting someone 80-90% your size shouldnt reduce gains -too- much, since that would limit possible targets too much over all.
A suggestion thrown out, then:
There could be a diminishing return kingdom-wise; similar to GBP but kingdom-wise effect to individual provs... KBBP... Kingdom-Bang Book-Protection :D
As in, after a few learns from one side of a kingdom there will be Book-protection added to whatever School effect a prov might have (EDIT: from that specific kingdom, not otherwise).
Idk about the numbers, perhaps up to 50% after 5-6 hits within a few hours? Fading rate i dont know... after 24h it is gone? After 12h it would still be 25% protection, in other words, and 3 more learns would kick it back to 50% protection.
Motivation: The intended effect would be to discentivice too many learns from one kingdom (a learn wave). Why? It will make more kingdoms end up in bottom-feeding frenzies and not be able to war-prep and find targets from a more stable ground. It seems to be needed because of the interaction with other settings, GBP and NW-diff/kd-sizes, but that might be subjects to be changed too.
In terms of role of the learn, it could push it more towards individual growing rather than kingdom bottom-feeding. Which I think would be a better place for it.