Three actual QoL suggestions I'd really love to see implemented:
EXPIRING DATES ON "CLAIMS EXPIRING" NOTIFICATION
Just like that very useful top-screen notification for Truces ending (which still should work better, as pointed out above), expiring dates of your Claims could be shown in a similar manner. Should both tools show precise dates for truces and claims in expiring order, not only would the fatiguing process of searching and checking all your claims be avoided, but you'd get a nice war calendar. I'm not the only one forging too many claims some twenty years in advance, right?
SCROLLABLE "AGE" TAB
Maybe most of you people play EU-IV on huge screens and fancy computers, but some of us just don't. If the only available game resolution is too small, then you simply can't read the bottom of the "Age" tab. "What does it say there? Oh, I must be emperor of China and adopt some cultures and.... well, can't read the last one. Probably not important". It actually should be scrollable. Please never assume your huge tabs fit everyone's screen.
MOVABLE LAND-BATTLE TAB (or movable land-army tabs)
Well, for the same reason as above, whenever a land battle occurs, the battle tab covers the army tabs (all of them, not just some - if you play at a low-enough resolution). Neither of these tabs can be moved around, resulting in extreme difficulties when trying to select the proper army to retreat. I think either should be movable, like most pop-ups, or some other clever solution devised.