Though the features added in Rise and Fall are hit and miss, I would not go back to playing without it. The positives outweigh my grumbles: the loyalty mechanic brings welcome depth to city placement and livens up your borders; achieving historic moments feels great and so does being able to review your civ's history; and overall there's a lot more of what was already in the base game (new playable civilizations, new wonders, etc.) which together bring variety and longevity to the experience.
But while we're here, I have two grumbles and they're both to do with the Great Ages mechanic:
1) It was much more fun in base game when the big "you have entered the renaissance era" (or whatever) moment was triggered by you researching a renaissance era technology. The new system—wherein you are pre-warned that "the world will enter the renaissance era" (or whatever) in X amount of turns, and then it just happens—feels passive and thus dissatisfying.
2) Because the points that you earn towards achieving a Golden Age do not carry over into the next era, players who have already met the threshold for a Golden Age are encouraged to make odd decisions and avoid triggering Heroic Moments in order to score the points later. It's a level of micromanagement that feels narratively incongruous.