I really see no real difference in the way the threads/posts are displayed for browsing through them... what do you mean exactly?
You can turn on/off the display of the "full post" or just the headline, so with only the headlines displayed, I see very little difference, functionally, from the old way. And yet when things are slow, you can view the whole text of replies in "latest posts" and find interesting conversations that are happening within threads.
As for the font size, you can control that in your browser (Or at least I can with IE 6)