I already can't go back to Civ V.
I think Civ VI offers more of a comeback mechanism than V. In BNW, if you are ahead in science you are most likely ahead in everything. Once a civ starts running away, it will be very hard to stop them, which means late game is just a boring next-turn-fest. In VI however, with the science/culture split and the fact that you can't buy out the allegiance of the entire map with money anymore, you have more opportunity to turn the tables. Religious victory is surprisingly a very viable underdog option, and a strong faith can secure crucial great persons for your strategy, or deny them to a powerful rival.
I believe late game in VI is already better than V due to the superficial diplomacy in the latter. If you have enough gold, you control the World Congress, which makes the inclusion of that feature itself kind of pointless. Sans the World Congress, there really isn't any late-game feature from V that is absent from VI.