I was thinking that anyone can access the site and do anything that they would do now. The only difference is that what you do doesn't affect other people until the freeze interval is over.

Freezing the content of the main page to update at a fixed rate makes sense.

The comments won't work as well if they aren't done in real time in the current format. One possible solution would be to add a separate section for active comment threads. This might serve as an acceptable way to slow them down, or keep them visible longer. However, the real time comments are a large part of what makes this site addictive, but it's also what provides a fair amount of the value.