Last night I hacked together a simple web extension for Chrome/Firefox to enable collapsing/expanding comment-replies threads.
I find it a bit annoying to scroll through long hierarchies of comments to get to bottom of page comments but that is my personal opinion. Would definitely like this kind of functionality baked into Codeforces.
The extension is open source and you can find the source here: https://github.com/chiragjn/codeforces-comments-collapser
Should I publish it to the Chrome Web Store/ Mozilla Store ?