1) reddit renders fine for me now, zoom is consistent (Firefox 32, Android 4.4)
2) HN uses HTML straight out of 90s (tables nested three deep, spacer images to indent threads) so I don't mind them not focusing on trying to salvage it. Also from the comments thread: "to fix this we'd want to know the widths of the containers of all the text, which requires doing layout on the whole subtree (or at least a decent part of it), but we need to know the inflation numbers before we do layout. (It's probably doable by constructing reflow states for the entire subtree as we walk it, but that would be a significant performance hit that I don't think we want to take.)" Don't abuse tables and you won't have a problem.
2) HN uses HTML straight out of 90s (tables nested three deep, spacer images to indent threads) so I don't mind them not focusing on trying to salvage it. Also from the comments thread: "to fix this we'd want to know the widths of the containers of all the text, which requires doing layout on the whole subtree (or at least a decent part of it), but we need to know the inflation numbers before we do layout. (It's probably doable by constructing reflow states for the entire subtree as we walk it, but that would be a significant performance hit that I don't think we want to take.)" Don't abuse tables and you won't have a problem.