Make buildings harder to destroy, easier to repair/rebuild?

After only several hundred years through my first ever game I guess I don't have as good an empirical base as most people, but my subjective impression is that building cost is already prohibitive while buildings are also very easy to lose if you lose control of your holding via siege — not even just assault but also normal siege can lose you two buildings at a time. This includes unique buildings such as Dragonstone that don't really matter much but are there for flavour, so their absence is missed. Of more practical significance is how castles on borders can easily be reduced to a permanent undeveloped state because with such frequent losses of control even through simple sieges (starving out etc., not wanton destruction) the lord simply can't hope to afford to replace the buildings. They're gone faster than built. This seems particularly bad with Castle Black.

Again, I don't know the context, I don't know how things were in older versions and what the balance looked like back then, what problems there were back then etc. So perhaps I'm missing something. However, it appears to me that the current balance is perhaps harsher than optimal, even for the cash-starved, low-econ, dark-fantasy feel we associate with ASoIaF. Could it be made more investment-friendly?

For starters, I would consider, if technically doable:

• Protecting unique historical buildings (Dragonstone, Painted Table, Moat Cailin, etc.), or at least making them rebuildable if destroyed. This is realistic because the destruction of such extremely fixed assets as the fortress of Dragonstone or some other such strong structure should require much more violence than just the usual sitout starving the defenders into submission that mostly consists in cutting off the supply and biding the time.
• Substituting damage for destruction. For example an event to repair (costs cash), demolish (gives cash) or wait some time with a risk of collapse.
  
• Enabling attackers who want to keep stuff intact to try and sometimes succeed, e.g. issue special orders to not use trebuchets, catapults etc., with some consequences (siege time, morale, cash, more loss of life for the attacker, etc.) and some chance of disobedience (e.g. commander/ruler traits, random chance).
  
• Restricting some of the destruction to deliberate act (event choice) by the attacker (such as on revenge CBs or when a war defender sieges a war attacker outside the defender's de iure, also based on AI traits for the ruler/commander).
• Increasing or decreasing reparations based on the amount of destruction.