If you found what you did on FFXI fun, then come back. Really, don't take pessmistic people seriously. They are addicted little idiots who like to think the worst case scenario is already happening... like gil sellers being unbeatable at ulli or something.
To spit some facts... server populations has hardly drop, maybe increased. The ratio of high level to low level has increased on the side of high level, but there are still more people levels 20 to 60. Getting exp post-60 has become very easy, for any job really, but there is a lot of elitism for merits at 75(but a NIN won't have a problem)... overall, there are a lot of very eays and rewarding monsters to grind off of now. The amount of content in updates is as its always been, now with some actual job fixes SE has been doing. There are more gil sellers, but things have hardly changed, expect to see more people in sky.
However, none of this will determine if you will have fun or not... if you care too much about imaginary swords or the kind of competition you get from chinese people who sell gil, you will probably not enjoy it. If you are willing to try new things, that take less time to do but are less rewarding then some previous content, you are more likely to enjoy it. The storyline has gotten very interesting if you are into it. A lot of quests involve small effort and can be done while seeking. It might be awhile until the big, new endgame area is released... there might be two, but, I'm thinking it(or one) will be released in the next two updates.
PS. If you can forget for a moment you are 75 and only care about getting stronger, the amount of content that opens up is interestingly large. Don't forget you are playing a videogame, not trying to increase your grades at school.
XI Wiki

all depends what LS you're in. I don't even know HNMLS's that go after either these days, lol
