To my knowledge, the current mechanic that only allows use of /ah inside a shop plot in nation capital is meant to make it so that /ah does not completely remove the need of travel. making prices less region-dependent and cargo movecrafts unnecessary. However the issue with this is that so far it has failed to create any real "trade routes" to my knowledge, and there are so many small nations that you can probably just find a random nation capital within 1000-2000 blocks from any town.

This means that only real consequence of the mechanic is that you have to occasionally run to nearby town and hop the wall to use /ah if you do not live in nation capital.

Another important drawback is that it further encourages creating small nations and/or breaking off from the current nation and making a new one. Server already has enough issues with too many people creating a nation.

The way I would solve it is as follows:

-You can not use /ah in neutral or enemy nation towns
-You can still use /ah in nation capitals
-You can also use /ah in towns that exceed a certain number of members (for example if it is "large town" or a "city")

I think that those changes would allow any town to eventually become meaningful and strategically important without needing to be a capital city.

I also do not think those changes would break any "balance" because as it is right now, you are not really restricted from using /ah by not living inside a nation capital or not being close to your own nation capital, since you are more than likely just few minutes of travel by horse away from a random nation capital.