User blog comment:Rupert Giles/Introducing Updated Global Navigation/@comment-11573386-20140924221632/@comment-452-20140924224105

I believe the answer will be "no".

Allowing communities to opt-out would be counter to the stated purpose:
 * we updated the look and feel of the navigation to be more consistent across all communities, screens, and devices.

I think it's highly likely that they will not even allow the colours to be changed.

But, as always, I hope I'm wrong.