I certainly won’t try to stop you from writing a plugin (or userscript) but such a thing would have problems for me to find it useful.
How would it know if it was something I wanted to simply skim or read and fully comprehend?
i.e. “skim” time would be much different than “comprehend” time.
Going by Title to get an idea of content and post count (though true, post content does vary) works fine for me.