Hi, I've been playing for a while and progressed to the later stages of the campaign so thank you for this wonderful mod.
I think I have noticed a significant problem with the economy though. It's summer of 2510 and basically every human clan is dirt poor, running around with parties of 12. Sylvania is doing great, Rich to Very Rich with lots of territories. What I think is happening is that Mercenaries might be sucking kingdoms dry and taking all the money. Every one of them is listed as Very Rich in the encyclopedia. During the early game I made 540/influence point which seemed high, but I don't know that might be possible in vanilla too. And not so long ago my fellow Reikland clans were Rich to Very Rich, and then Sylvania declared war and Karl hired 3 mercenaries. The contracts all ended not so long after and Karl and one other clan were Poor, despite having plenty of fiefs each. The other two AI clans were still listed as Rich.
I'm not entirely sure that mercenaries are the problem but this might be something that you want to investigate.