Mid-tier I would say. What usually happens is that clans start going to bankrupt, and lords start disbanding units but at the same time they continue upgrading them. The money invested on these upgraded units is a waste, because they disband these upgraded units after some days too.
Mexxico added an AI behavior to stop recruiting when lords' parties reach the wages limit, and maybe they should also stop upgrading units. I know that this could be a double-edge sword because people could complain about lords having too many low-tier units, but it is also a bad thing to having to face really small lord parties. Plus, most part of these upgraded units are going to get disbanded after some days, so the AI is spending money unnecessarily. The new system for limiting AI parties' wages is great but it needs some polishing. If I remember correctly, before this we had a system where the AI did not pay wages if clans were pretty low of money, and I have the feeling that devs have replaced this system with the new AI limiting party system, but now the AI needs more money. Maybe it is just about increasing taxes a bit, while increasing prosperity and adding some buildings for some kingdoms fiefs.