I defintely agree with you on this, and always have. UU's, UA's, and UI's, as well LUA's, LUU's, and LUI's, together should have a significant amount of usefulness, collectively across a large arc of history, not just the snapshot of the given leader's life and times, with no meaningful strong abilities before or after. I admit, though, it does tend to handicap civ's with much smaller attested history, but creativiity is key, there, I think (like, as a random example, some hunting bonus for Lakota or Cree could translate, effectively, to a preservationist eco-hunting in the Atomic Age without necessarily having to change the specific bonus).