I use linux exclusively and I think one of the smartest things any company can do to promote their product based on linux is NOT to use the "Linux" word on their front facing promotional material. Just the mention of "linux" means it's something potentially weird, non-standard, for nerds only, lame or just doesn't work like most non-linux users expect to the majority of everyday users "out there". I'm wary of Canonical but from a marketing viewpoint they have the "don't mention it's linux" thing totally right if they hope to gain real-world market penetration.

As for the GPLv3 license + CLA, if they put in 95% to 99% of the codebase for Mir then jolly good on them for coming up with some strategy that allows them to provide a strong fiscal base to support lots of developers and support staff. For those who don't want to play along there are already plenty of alternatives so why not give them the good grace to try a dual license path... like Trolltech, and others before them.