Actually, even with that, I think it may not be enough. Maybe nation prices should be increased to reflect towns. So like it would cost 1k for every town in your nation or something like that. Many towns abuse nations by gaining a huge boost in plots allowing small towns to claim more plots than they normally would with residents. Thus, I think it would be logical to increase the cost of nation tax.
Also, I don't think town taxes for plots need a decrease. If anything, if the nation tax thing doesn't go through, it needs to be increased to help nerf large towns from claiming a large amount of land.