I have a lot of fond memories of XI, but I wouldn't play the game again.
Sure I would love to have more expansive zones, but I remember 1.0 zones well and I'm MUCH happier now.
Sure I would love for XP gain to be lower... but then again I learned everything I needed to about the combat system so having it take longer wouldn't really have *taught* me anything else about the game, just made me feel a bit more accomplished.
I already have fond memories of XIV, unfortunately the thing I seem to have a problem with is that PEOPLE in the game are ephemeral.
*ramble ramble ramble*
I honestly don't think it's the game that's lost it's magic, but the players desires to work together to accomplish short and long term goals with one another.