I believe that the Vampire Counts are in serious need of another rework. I previously made a post about the Dwarfs, and I have also made a post a long time ago about how the Vampire Counts could be reworked in the future. I'll leave a link to that post here (https://forums.totalwar.com/discussion/268738/suggestions-for-future-revisits-to-the-vampire-counts#latest
Now, I don't wanna talk about any of the points I made in that post. Not about most of it at least. I wanna focus on corruption; with an emphasis on vampiric corruption.Vampiric Corruption
I think the Vampire Counts need to have more emphasis on a scheming and plotting playstyle in comparison to other races. Especially since they're surrounded by enemies and cattle on all sides. Their corruption mechanic is already a great tool to contribute to such a playstyle.
Instead of corruption just being a public order penalty and giving corruption to living armies, what if the more vampiric corruption a region gets, the more diplomatic bonuses the local living faction gains towards the vampire counts, but also loses towards other faction living factions?
If the affected faction is human and reaches too high vampiric corruption within at least half of its empire, then that faction will become susceptible to being vassalized by the vampire counts.
Also, above a certain threshold, the vampire's influence makes the faction more willing to break their treaties with other factions. This way CA doesn't have to give the vampire counts another influence copy-pasta treatment and this becomes a more interactive way of sabotaging your opponents.
Trade agreements should also spread vampiric corruption into a trade-partner's regions. Imo, abandoned regions should also spread.Chaos Corruption
I think one good change would be for regions with high chaos corruption to make them uncolonisable for about 10 turns. The corruption in that region must be lowered to a certain threshold for it to be colonisable again before the limit. This limit could maybe be extended through technologies. After the 10 turns, the region should be recolonisable again, but if it has a Herdstone or Chaos Gate, then the colonizing army has to face a beastmen/daemon army that functions the same as a garrison. It would also be cool if the higher the chaos corruption is in a region, the more winds of magic there is within that region AND it will also mutate your forces and inevitably give them an ability that might turn them into chaos spawn in a battle. We're already kinda getting something similar with the new Moulder mutagen mechanic. Retaking regions from chaos should be a war of attrition and pure hell.Skaven Corruption
Skaven corruption should give a chance of spawning an undercity in a region. Undercities should also cause skaven rebellions once demolished to add a risk factor into getting rid of them. High enough Skaven corruption should also lower the line of sight of a region and your armies within it.