As people have already mentioned, I think retaining the general limitations of lower polygon count and lower resolution unfiltered textures but enhancing the visuals with something closer to a "beefed up" PS1 is what most people are talking about here and would like to see more of.
Which is basically something like NDS level graphics rendered in a much higher resolution (shamelessly posting Krammy's wonderful gifs):
The Wizard of Oz: Beyond the Yellow Brick Road
Solatorobo: Red the Hunter
Phantasy Star 0
Golden Sun: Dark Dawn
Nanostray 2
Avalon Code