I would like to vote against having a publicly-visible "like" or "vote up/down" option. While I understand the desire to give a +1 without cluttering a thread, I think on the more political or contentious subjects it would just degrade the discussion to the level of a popularity contest. (I suppose the same argument could be made against internet discussions in general yet the mustache community manages to rise above it. The tool is as good as the tool-user. Still, why tempt temptation.)
I would like to recommend a "show most recent posts" option. That is, not the most recent unread posts, and not the most recent posts by category, but all most recent posts regardless of category. The problem is I'll read a thread, not comment on it, then think of a comment I would like to add later, but I can't find the thread again because I originally read it via "show unread posts since last visit" and didn't note which category it was in--OH SNAP, I just realized that is a feature all the way down at the bottom if you go to the home page. Nevermind.