>> "The bevel is bad" is not a very good argument, either.
While I don't like the logo at all, I have to agree with this.
Yahoo's logo isn't designed for logo and design aficionados, it's designed so that the masses can easily associate the shapes and colors of the logo with the company (which leaves me to wonder why they fixed something that isn't really broken). Most people don't think much about the logo beyond that.
The exercise of rebranding itself is just a PR stunt to tell the world that Yahoo's not the old Yahoo.
Traditional (i.e. Paul Rand era) logo design was trying to distill a company down to a minimal essence. Having bevels leaves in a decorative element that makes in non-minimal. That it should look good in 1 color is fundamental to traditional logo design.
Yes, but it is going to be used on the screen 99% of the time, you say. But people who violate that rule end up with logos that are just a little bit tacky to a graphic designer.