With theme parks that have the kind of end game found in FFXIV:ARR, there is a social phenomena where people play the game in waves. Starting at some point close to when a major content patch is released, the population of active accounts increases. It then peaks after some arbitrary amount of time and begins to decrease until another content patch comes out. I generally feel the health of the game is waning faster than it should for a MMORPG only released a year ago, but that is based on my own preconceptions rather than actual data. Without statistical data it is difficult to say how well the game is faring against the current MMORPG average.

That being said, it is difficult to compare FFXIV:ARR to other MMORPGs because the only two current P2P MMORPGs are niche games like Wildstar and Elder Scrolls Online, both of which were never designed for mass appeal in the first place.

So my general reaction is "who knows?" Only SE really knows what's going on at this point.