Don't even need a texture pack to make FFXI look better. Just need a new rendering engine that isn't dumping all the visuals to a flat texture to then stretch to the screen size.

There's room for much better bumpmap lighting (as it stands, it barely exists outside of 'day' and 'night' and that one second transition between the two come 18:00), native anti-aliasing that doesn't involve doubling the rendering texture resolution to something like 2048x2048, increased draw distance, unlocking frame rate from game logic to let us hit 60fps, and a less aggressive LOD so you don't see props like trees painfully popping up with more detail from 5' away.