Yep. I bet a hotpot dinner that this Google+ new home will aggregate all your content, including mails, and become the default home for Google, which would explain why currently the logo on Gmail is not a link anymore.
The logo doesn't do anything on several Google properties, not just gmail. And actually prior to this refresh it didn't do anything on G+ either, which annoyed me to no end.
They made this change a few weeks back and I honestly don't know why.
