If you read between the lines, there is a very good reason we continue to see only new games on next gen systems. Simply put, there is no way anything produced today can live up to the standards of expectation surrounding golden age games like Secret of Mana, Chrono Trigger, FF6. Now that they're remaking X, that theory doesn't hold as much water as it might otherwise. But what is really involved in a PS3 remake of a PS2 game?
It's hard to be sure just how Square plans to "remake" FFX, but it seems likely they chose this as their first experiment in re-texturing and putting a glossy new coating on a game that still uses most of the same polys and a modified engine. Not to sound excessively jaded, which I am, but the theory in business is generally to make the most money for the least amount of work. So it seems plausible that Square will forgo redesigning the combat system and anything else that requires extensive production time in favor of tweaking character models, spell effects, anything flashy, and slapping a new UI/menu screen on it.
Assuming that is the case, here's why I think Square fails to deliver in providing us with next-gen remakes of VII, VI, IV, or any of the other more dated FFs. Standards are much higher today, considering the industry is so much bigger. Old themes have been done and re-done, producing jaded gamers and reviewers alike (Hello world!) who cry when a game doesn't offer something new. On the other hand, there are the purists who want everything to stay as it was.
But the harsh reality is that these games weren't really as good as we remember them to be. Our fond memories of games like FF6 are because they were groundbreaking at the time, and we enjoyed them for what was being offered. That's not to say that they still weren't amazing games for their times, and still worth replay value even today. But games have evolved, and many of the amazing titles of yesterday would not be any more well received if offered up as a next-gen remake. In fact, they would probably do much worse.
See, X was the first in the series to feature voice acting. It was also the first in the series on the PS2 hardware, which gives its content a comparable standard to current gen modeling standards. This makes it optimal to work with while new textures and hardware do the majority of work in making a game designed for the PS3 look different from one designed for the PS2. So to choose FFX as the first title for a series of updated remakes isn't really surprising.
Also, much less was actually being offered in the older games (for the sake of argument, lets call this pre-FF8), at least as far as visuals and audio are concerned. Character development and story carried the games much more than they do today, and much more was left to the imagination. Part of the reason there's a fond nostalgia associated with 2D sprites is because there is room for interpretation and less harsh criticism of every pixel or design aesthetic chosen for Noel/Tidus' outfit. But FFX already has that sort of criticism associated with it, so Square isn't really going to be providing anything that can "ruin it" by changing the aesthetics of the game.
The bottom line is that people are opinionated and not afraid to voice their discontent regardless of whether the opinion actually has merit in deeming something a bad game. The more there is to criticize, the more chance there is that the community will fragment over something trivial: EG: Chocolina/Noel Pants/Tidus Voice/Quicktime Button Press Events.
Such is the way with the gaming industry now. These things weren't present to criticize back in 1994 (FFVI) because the technology wouldn't allow it. Not (entirely) because the team has changed since then.