I think these ideas make for an interesting game. One idea you mentioned that really caught my eyes was the concept of a progressing civilization. This can be taken to a number of different levels. You could start out in some run down farming village, helping out to improve the settlement and gain reputation by collecting resources to build up the village, helping the inhabitants with their daily tasks, defending from monsters, etc. Eventually, maybe, the settlement might start spawning other settlements, bringing it to a sort of "province" level, at which the settlements you helped build are interacting with the other parts of the kingdom, at which point you might start gaining reputation with the kingdom as a whole, and maybe later get an official position in the kingdom's government.

Another idea this brought to mind was the concept of events occurring as time progressed. Sort of like... there are certain "prophecies" (I.E. of a demon or monster of some sort attacking the land) that come to pass at certain parts of the game which you have to deal with. Or maybe not even events that statically occur, but wars that might start or natural disasters.