Agreed. I'd only add that might need to nerf end-game exploring a bit if we implement these changes. With only 4 kingdoms, it's going to be even harder to throw away a kingdom (usually your strongest) on a suicide.
Hmm, I've no idea about the exploring formula but from what I can remember its a bit too expensive early round and a bit too expensive late round while being too cheap between 2-4k acres where after the price is almost unbearable. Pretty smart of wilan to use this to his advantage and convert to explore early:)
If you observe a full round explorer in a 5 weeker you'll see that they'll be leagues behind, catch up massivly mid round and become one of the top kingdoms and then fall behind again end round. or that's how it usually goes.
The previous semi explore wins I have witnessed, has always been massive land leads from attacking, where you convert with the purpose of defending the lead. This is the first time I've ever seen someone "run away" exploring. If its due to how overpowered tollsprys was or due to the fact that exploring is too cheap at mid round acrages resulting in cheap end round exploring because of the short round, or a combination of both I cannot tell.
Exploring is a passive play style, and I think that's the last thing we need more of, even if its balanced it wouldn't hurt to look over the cost atleast for mid size acrages.
Short version: No more 4 weekers please:)