Yes to both suggestions.
Perhaps we could go deeper into the nested comments by having the right (blank) side column disappear when necessary.
This may sound revolutionary, but we could even have an option to make the left column disappear when necessary.
I think it'd be a good idea to keep a list of the ways we'd like to see LessWrong improve, sorted by popularity. Ie. email alerts for new responses.
So if you have an idea for how LessWrong could be better, post it in the comments. As people up/downvote, we'll get a sense for what the consensus opinions are.
I think there's a pretty good amount to be gained by improving LessWrong.
Note: I say "ways to improve" instead of "features" because "ways to improve" is more general.