Never really been a big Uematsu fan, but that isn't to say he hasn't made good songs now and then. I find it funny he considered IX his best work in the past, but I felt it the worst in the series in terms of memorability and engagement. One of my larger issues with him is his reliance on synthetic instruments, and it's something he's been using long since hardware has been able to support more orchestral or "living" sound.
I think you're sort of answering your own question. IX had a great soundtrack precisely because he (mostly) used realistic instruments instead of early 90's MIDI synth. Many of the tracks were lighthearted for a change, Melodies of Life was actually tolerable compared to Eyes on Me, tracks like You're Not Alone! were emotionally moving, and there was just as much classic FF nostalgia in the music as the game itself. Dark Messenger was pretty hardcore, too. The use of recurring character themes was also different and I thought made the tracks more memorable. This all coming from someone who also isn't a big fan of Nobuo.
Whatever the case, being on the "Nobuo is good, but not the greatest composer in the history of ever" boat is just as tough as being on the "FFVII was good, but not the greatest RPG in the history of ever" boat. Of note, Nobuo worked on a good chunk of FFXI's pre-expansion music, which may explain why you're not a fan of the main cities (I'll admit though, Whitegate doesn't bother me nearly as much as Sandy and Windy).
I actually rather like the new song, its a lot more complex than the others.
There's beauty in simplicity, you know. Unfortunately, there's really nothing complex about this track. Listen to the melody, the chords, and how it all flows, and it becomes hard not to notice the lack of structure and patterns. Complex songs can be fantastic if enough thought is put into them, but I really don't think Nobuo did more than just improvise a tune in the shower here. That doesn't mean it won't sound good to some people, but those with more discerning ears will naturally find it lacking. I don't mean for that to sound elitist, it's just that Nobuo isn't really living up to the reputation his rabid fans have given him here. Anyway, you can argue that it's only one song, but as has been mentioned before, this is one song we're going to be hearing over and over and over for years