Barbarian Invasion - Random Events - Fortifications

During my current play through that was rife with betrayal, spies, and wars all over I felt that the game was lacking a certain random event feel. I think that the below items would enhance game play in a variety of ways.

1: I have noticed that in each province there is some sort of center marker - I do not think these have any purpose other than simple eye candy. I would suggest that whatever item is in the center give some boon or boost to a 100% tribe owned province. Or alternatively they can build a stronghold in the center once the area is 100% owned. This leads into number 2.

2: I have also noted that there are rivers that denote "Kingdoms" - I would suggest that once a entire Kingdom is owned the tribe can pool some extreme amount of resources into constructing a fortification (super villa) that will lock down that area. This could be the tribes central hub - once constructed it could be a housing place for resources/coins/nobles that are pooled by the tribe - perhaps also giving boons (like the skill tree) but in special units or upgrades to units the tribe owns.

3: Map changes with current year cycle - always green grass is ok - but a visual change to the game map as the seasons roll past would be a tasteful change.

4: Random events - random map events that change game play - for example a large flood blocks off a certain area of the map - or locusts swarm province x making farms and provisions lower - this could be anything really from weather affects on tiles in that province to affecting recruitment speed.

5: An end game crisis - I am sure all those barbarians are pissed always being farmed and attacked. As the game world drags on ever increasing levels of retaliation from the barbarian villas could arrive to raid against the players. Perhaps even a mass invasion with nobles striking at the best players/tribes.