I don't like how on the main thread list, you have to scuffle your eye sockets all the way to the right to see when the last post was. Meanwhile the date and time when the thread was started, which doesn't matter at all, is right there for me to see right away, for some reason. It's very poorly thought out, you'd think the last post date would be something you can see right away, and the "thread started" date can be a bit off to the right, so you can look it up if you want to, or whatever.
Other than that it's a slight push away from the 90s in terms of the design and UI, which is welcome. And I was just on a long vacation, so this is a perfect time to welcome me to a big change. Otherwise I might have been whining about colour changes and such, but because I just got back from Japan it's like the old design was a part of the pre-Japan days, and this new design is a part of my new identity. It's very fitting, thanks for coordinating the upgrade to coincide with my return
edit: I also don't like it how when you click on a thread, it takes you to the 1st page and 1st post, as opposed to the last page or even the last page you were previously on. I realize that the little page numbers are there for me to click, but surely clicking on the thread title shouldn't default to the 1st page unless you have never been in the thread before.