6. Final Fantasy XIV
Final Fantasy XIV went from a complete disaster at launch, to a supremely popular MMO over several years. That's no small accomplishment and it would have been impossible without consistent updates.
Final Fantasy XIV launched 8 years after the series first MMO (FFXI), despite concerns from the community and development team over the state of the game. Unsurprisingly, the game was a mess when it released; a horribly designed UI, confusing world & map, baffling levelling-up system, time-coordinated content, no post-game content, and incessant lag. These problems truly just scratch the surface of FFXIV's faults and it led the series worst-ever Metacritic score of 49.
It's difficult to stress how bad the situation was but suffice to say, Final Fantasy XIV was very nearly just that: the final fantasy. Amazingly the team at Square Enix decided to completely remake the game while the original was still available and being updated.
Final Fantasy XIV: A Realm Reborn was the complete reboot of the game that released in 2013 and it mercifully killed the 1.0 version. Since then, there have been sixteen updates, including two massive expansions, and XIV is now considered a great game with a Metacritic score of 86.