Not really. The vast majority of VG composers don't have formal training either but they still produce immensely great soundtracks.
The problem with FFXIV 1.0's soundtrack is that it flat out didn't fit the game. The tracks themselves are actually really well done both thematically and in terms of presentation. The issue is that unlike his former offline games where he's involved in the process and can see what the shape of the game is going to be, and when the soundtrack was finished (before alpha even *started* and zones weren't even completed) he was flying blindly.
Flying blindly is what reduced the soundtrack to "Meh" standards. Lost Odyssey's shown the man can progress and mature with a completely different feel to his music and still be enjoyable. While I couldn't be bothered to finish the game, The Last Story's title screen theme showed he hasn't lost any chops on emotive feeling either.
FFXI still has perhaps the single best soundtrack of any MMO in existance and they aren't ambient tracks by any stretch of the imagination. There's a solid thematic, cohesive theme that exists with singular and modular melodic content. Ronfaure is still one of the most gorgeous pieces of music I've ever heard from a video game (Uematsu). RoZ and beyond showed that MMO music can lend the atmosphere of ambience but still have a definable and catchy melody.
WoW has ambient music soundtracks: they're absolutely terrible and utterly forgettable. AoC had an ambient music soundtrack: terrible and forgettable. Its follows on with almost every other MMO (and even most games in general nowadays) that ambient music doesn't really have lasting appeal because it's there simply to have something to fill the silence -- it's not designed to evoke recognition.
I'm having a difficult time reconciling your two arguments. On one, you point out that most video game composers don't have any formal training (which I'm not sure how true that is), and then on the other, you point out that most video game composers don't do a good job. So... I agree? But I disagree with your conclusions. First of all, Uematsu is simply not strong to me in producing the kind of music needed for an MMO. That's not to say that he hasn't done it... but it's a pretty short list of expositions.
Secondly, we can quibble over my use of the term ambient music, but when I say that a track needs to be ambient, I don't mean that it can't be an orchestral composition. There are a great many orchestral compositions with an ambient quality that also evoke great feeling. While Ronfaure was a great piece of music, it also clocks in at a scant five minutes of music. Someone who spends an hour in the zone hears it 12 times. And this is where an ambient break would have not only given the song a break, but extended the track significantly and improved the atmosphere of the area.
Also, while starting your arguments with things like "Not really," and "Incorrect," may help you to feel as though you are conveying an expertise in your opinion (or maybe that's really just the way you talk), to me it just reads as you being rude and dismissive of the opinions of others. It's like saying, "You're wrong," instead of "I disagree because..." It's the way people talk when they think their opinion is the only one that matters or counts. So as a piece of constructive criticism, if you'd just left those out of your replies, it would have still been clear to everyone that you disagreed with me, while maintaining a more respectful discussion. Just telling you this because my brother does the same thing, and it earns him no points with anyone.
Ok, now we're going to get slash fiction of Wint x Kachi somehere... rule 34 and all...
Never confuse your inference as the listener for an implication of the speaker.
Good games are subjective like good food is subjective. You're not going to seriously tell me that there's not a psychological basis for why pizza is great and lutefisk is revolting. The thing about subjectivity is that, as subjects go, humans actually have a great deal in common.