I don't like the site's visual look, but I think that they made this change for the engine running underneath the hood, so to speak. I think that for the future, this is probably going to be an improvement. Didn't they have problems with the old engine not being flexible enough and running out of memory or space? And we have the Search feature back, although I haven't tried it yet, still trying to get used to navigating around.
Seems to be kind of redundant to keep listing every single reply to one topic, should only have to list the latest reply since you will probably see all of the previous ones anyways once you get to the topic itself.