I just find the new forum look awful. The old one was unique.
The look doesn't matter that much, the functionality does. AFAIK there will be more themes/this one won't be default (?). I dislike the current one as well.
So new functionalities are coming ? What about translations of the menus, the buttons etc. ? That would be something I would love and to which I could contribute. If a "retro" theme, like this one is available, I won't have any regret to switch to the new forum software. Also, a little functionality that I would like would be that you would get PMs from the forum when you someone replies to a thread you marked, as a kind of notification+, but maybe all this is off-topic and there's a dedicated thread to functionality suggestions.