Is the lack of chroma subsampling options a characteristic of webp itself, or is it an issue with xnview's implementation?
If it's a characteristic of webp, then webp is totally useless. The quality is as bad as jpeg has the reputation for (due to subsampling), yet the filesize is actually LARGER than the original (but higher quality) JPG.
edit: It seems that I misjudged the original quality setting of the jpg that I started with. After using comparable settings with webp, the result was approximately 1/4 smaller than the comparable quality jpg (with the jpg resaved with the same crappy subsampling levels that webp is stuck with) & has the same subjective quality. Still, the lack of subsampling options limits webp to extremely low quality images.
Oh the feuhrer, oh the feuhrer, oh the feuhrer's nipples bonk!