By in large, I agree with your review. However, I would have given it an even lower score in the graphics department. Let's face it, Abyss is a terrible looking game. It's my favorite in the Tales series, but it's a graphical mess: super generic, bland, colorless. About the only positive thing I can say about the graphics, is that I grew to really like the 2D menu system. I especially like the character portraits taped onto the screen with scotch tape, great little addition. But you know that 2D is designed by another guy/team. They deserve props, the 3D design staff, even if they were under budgeted (and I believe they were), didn't do a very good job with the resources they were given. Coming two games after Symphonia, one of the smoothest, slickest games of the generation, Abyss almost looks 64bit generation in comparison, and it was released after the 360 made it's debut. I've always pointed to Abyss as a reason why the PS2 was technically inferior to the gamecube... but that probably isn't fair, as the Tales team could have done a whole lot better.
That said, graphics are pretty much the only thing negative about the game, and at the end of the day, that's probably the least important aspect to me in a good RPG. It's able to avoid the shear slew of techno-babble and fanto-babble that tends to plague other games in the franchise, and as you said, the characters are much much more developed and their dialog is some of the best in the genre.
That said, even being one of my favorite games on the PS2, I have no interest in getting the 3DS version. I've played it through once alone, and twice assisted friends through parts of their playthrough. Maybe in 10 years I'll get the itch to replay it, but by then, who knows what system will be able to play it.