1. I don't think there ever was a country tier level 4. Where is it referenced? Perhaps it's level 4 of something else?
Either way, I would've only removed researches if they were unnecessary anymore, not to cut content for no reason. There were also several new researches added, so I don't think we have a problem here.
2. There is no recipe for katryx weapons besides the blade. It's the only weapon of this type. There are 4 katryx armors, which you can craft once you have the recipe, but no other weapons.