Comment on WordPress Gravatars by Mark.
I agree with your analysis of nofollow. Therefore, I am testing another recent comments with gravatars that does not seem to have no follow. It is called “Wizzart – Recent Comments” Some Austrian guy put it together and it has excerpts, so it is a little more robust. I do not know if the excerpts are good or not.
My initial results are people are clicking more on the Gravatar recent comments, but not enough data to tell yet.I am often optimistic too early but the idea is sound, that is people react to faces.
It also has an alt tag on the images that default to “Gravatar for Mark” which I do not know is good or not for SEO.
Maybe a better alt would be “comment title + Mark” or something?
Or maybe as is it is good to go.