There have been very few total relaunches in MMO history, so marking Final Fantasy XIV as having one of the best isn’t exactly disputed. There’s also not much room to debate on whether or not the relaunch was a success. But some of the systems the relaunch has changed up have been made either no better or actively worse on the conversion; cross-class skills, for example, are not in a good space. By contrast, Star Trek Online is in the middle of revamping its skill system yet again, and while that might have issues, it certainly looks to be a positive change.
Revamping systems can always be tetchy, of course – sometimes it works and sometimes it doesn’t, and there’s always the issue of players who liked how things were rather than how things will be. But the revamps happen just the same. World of Warcraft revamped its entire talent system, Star Wars: The Old Republic revamped its stats and companions, and the list goes on. So what MMO have you played that had what you see as the best revision to an existing system? What major changes did you find made the game not only as good as it was before but even better?