Rise and Fall is....alright. I played a lot of Civ V (the best civ game for me). Civ VI was generally a letdown, but I felt like it was really, really good for a vanilla release. Unfortunately, the patches were also a bit disappointing.
I waited nearly a year to get R&F and honestly, I'm disappointed all over again. Half of the mechanics are good, but not great and the other half actually make the game less enjoyable. The new civs are fun additions, but they're all pretty bland in design. I bought R&F and found myself thinking "How can most of these ability lists turn me off more than a vanilla civ I've played before"? I'm one of those people that likes to win once as each civ before replaying any too.
If you don't like VI, R&F won't make it better. If you like VI, theres a high likelihood that you'll like R&F, but theres a chance you won't.
I can't believe I'm typing this, but I feel that the DLCs are way better value for the cash.