Not something I would want to take on if given the choice either, a massive task and as we still have old posts HT has done a great job..
What isn't liked by people is change. I don't like change but websites have to move with the sway of the internet and the days of the old style forums should be a thing of the past. Everything is media, social, twits, I mean tweets and sharing your bodily functions with everyone. Old style sites will all have to move at some point.
Something else which causes change are things users don't see and that is what software is running on the website server. As newer versions of that software is installed, older methods are removed, when they remove the version of the method you are using the website stops working, so site admins need to be ahead of this.
I like the new site, it is just different, but in keeping with the rest of the net.