I don't think the current one looks bad. I would even say the design is great. Maybe not aesthetically, but its very functional and is consistent with the purpose of the site.

The proposed redesign has too much transitional volatility associated with it. Although functional, subtracting from the current width makes the site look weird. Theres also too much text on the front page which is a departure from the way forums typically work with just the thread title (submission) and other essential info (comments, etc.).