True. The default tileset is better than most attempts to improve it. DF is designed with CP437 glyphs in mind so it's no surprise it matches the objects better than other ASCII fonts. Partial graphics packs just suck when they alternate between graphical and asskey tiles and there are no full graphics packs.
But instead of the default resolution I recommend making a scaled-up (nearest neighbor ofcourse) variant of any the default CP437 tilesets (whichever aspect ratio is your favorite) and play in fullscreen. Same as with most roguelikes.
The default colorset however needs changing, it's just pure eyerape.