For me the 5 avatar thing is extreme noise on meta cause it basically does not matter to me when I am browsing meta.
I read all posts in all topics, so on the list all I care about is the last poster and creator as an extra, albeit weaker, clue (which is one reason I opted to have creator in text and not as a picture).
I think there is some credibility to the complaint that the 5 poster thing can be viewed as information porn by some users and information overload to newbies. I also get the power it provides.