ideas for sieges

I was thinking about a sieges and would like to add some ideas.
Generally I would suggest that sieges do not happen that often and not in "additional" scenes. The siege should be in or at least close to the settlement and that does not (necessarily) mean enemies are plundering your lot.

I guess in every town there is a spot that is a little bit far off and at those spots the invading troops and the defenders should fight each other. For example it could be a special castle size lot...let's call it event area...that is normally empty and not claimable by anyone. But if a siege appears the attackers build a raid camp on this event area....nothing too big just some palisades, tents and similar decoration.
Basically the camp is build out of different zones. The more you get close to the central building the stronger are the enemies you have to fight.
From time to time a hand full of guards is attacking the outer regions of the siege camp but normally just we avatars can destroy defensive structures and finally destroy the central building to stop the siege.

Maybe even the attackers could vary.
The obsidian order is building some kind of portal as central building that is from time to time teleporting reinforces from a distant region. Their camp is build like a snail shell with gates that separate the shell sections.
Bandits or animals build a central earthen mound that is connected with an underground network to generate new enemies. Around this mound are some outposts you have to destroy first.
Evil druids build some kind of elemental shrine they are praying at to generate elementals. Their central building is in the middle of maze with walls out of lava, spiky bushes or something similar.
And so on.

Even if guards call to arms and some vendors might be nervous the normal "avatars life" would not be interrupted as the fight would be just round the event area but normally I would like it if sieges would have consequences...at least something like resource prices (coal, wax,...) in this town are 10% more expensive until the siege is removed.

Also I would suggest that participating in a siege is more rewarded.
Maybe a guard captain is simply paying a Bounty for each killed enemy...but if possible I would suggest something else.
On starting the siege the invaders carry resources packs into the camp and the longer the siege last the lesser resource packs are available...simply because they are using them. But reverse the invaders are plundering the town and that way gain e.g. plunder packs.
A siege starts for example with 100 resources packs. Every 10 minute one resource pack is consumed and one plunder pack is created. So basically in this example a siege would last 16.6h until all resource packs are consumed and the invaders leave.
The more resource packs are consumed the more robust are the defences and the stronger are the attacking troups. E.g. a siege starts with T2+ enemies, after 50 resource packs are used they are upgrades to T4+ enemies and if 75 resource packs are used they are upgraded to T6+ enemies.
I guess the packs could be something like the random loot bags we already know but maybe the resource packs are more likely filled with resources (food, wood, ore, weapons,...) while the plunder packs are more likely filled with wares (paintings, recipes, mugs, gold,...). That way the reward also depends on the needed time to free the town.
Depending on your participation you gain temporary siege points. E.g. you kill a T2 enemy you gain 1 siege point, you kill a T4 enemy you gain 4 siege points, you destroy a palisade you gain 10 siege points and so on.
If the avatars are able to destroy the central building within the timeframe (e.g. the mentioned 16.6h) the current resource and plunder packs are divided among the participating avatars as reward. E.g. for each full percentage point of the total siege points you get one random pack. (You collected 12 siege points and summarized there where 200 siege points collected you will get 5 packs as your part was 5.1%.)
The colour of the pack is randomly chosen. E.g. 80% gray, 10% yellow,...

As such a change would eliminate the need for the current siege scenes I would suggest to change their usage to large scale combat areas. Basically from time to time but a lot less often than a town siege the obsidian order is besiege a larger area by blocking the bottlenecks to that region. (e.g. all roads that lead into the Perennial Coast region.)
Those bottlenecks are not connected to towns and could be seen as additional combats scenes that from time to time appears and as an additional change and to make it a little bit more interesting I would suggest that the combined tiers numbers stay always the same...so to say if they lose one bottleneck they focus more on the remaining ones.
E.g. There are 3 x T4+ siege scenes blocking a local region.
After one siege is cleared the two remaining are upgraded to T6+ siege scenes.
And if there is just one bottleneck left this one is upgraded to a T12+ scene.

Ideas?