Not sure why you were downvoted, but I completely agree. I get the 'Unknown or expired link' message all the time because I'll write long comments, or write part of a comment, get sidetracked, then finish. There's no reason for this error message, and to have tokens time out after what feels like a matter of minutes.

Then of course this happens on the homepage too, when you click 'more', after being inactive for a while. Why?

And why is there no pagination?

Why do a click reply on a comment and get redirected to a completely separate page, instead of replying inline? And then when I submit that comment, it just redirects me to the top of the comment page, so I have no idea where I left off, and now the comments might be shuffled since votes have changed.

These feel like critical changes that benefit everyone, and require little work. Why are they never addressed after years?