With the way that Nations sieges go, its getting to the point where we as players don't even have time to build or do anything nation-building related. Every week, starting from Monday, we have to prepare ourselves for sieges, and then rinse and repeat the process. Nations I believe shouldn't just be all about Sieges, it should also be about Building Nations.
Therefore, I suggest that for every 4 weeks or so of sieges, there's should at least be a week of "Peace", aka no sieging, this will allow people the opportunity to do some Nations Developing. Now I get that people will try to abuse this to occupy their enemies for longer, but that can be avoided by making it so that you don't get occupation taxed as much, or no occupation tax during those weeks. But either way, having the chance to actually Build & Develop Nations without worrying about Sieges will keep players invested in their own nations, and will stop people from having burn-outs and quitting.