On a closer look it appears to also affect the 3D character preview window in-game as well as in character generation. So it's the entirety of the UI that gets upscaled/interpolated and thus blurry.
When running higher resolutions than 1080p, the interface seems to be scaled. This makes the UI elements, particularly the font, fairly blurry.
On my 1920x1200 monitor I've had to bump down my resolution to 1080p to get crisp fonts. Is it possible to disable the scaling of the UI so it runs at it's default size even when using higher resolutions?