i'm just wandering but regarding your question ( KojiroTakenashi), this new filtering modes were just a question of time, till someone remenbered that snes9x does that with openGL estension...and we all know that snes games rarely have 3d graphics (it's all done with sprites).
So i'm guessing that the sprites smothing is done the same way (more or less) as the snes9x estensions, if not....well that was a good idea, right? (it would cut some time to pete if he got borrowed that part of the snes9x source from the author)
If a code similar to the SuperEagle engine, or maybe the engine itself, could be applied to sprites and text.
What's odd about this mode, though, is that alot of FF4 seems to be completely unfiltered or smoothed with the new option.