I agree that mobile is critical to remaining relevant (along with security), two areas where Mozilla/Firefox have been pretty subpar. I don't think Eich has specific security or mobile expertise, but he is quite technical, which is a big improvement over a lot of potential CEOs, and I think a technical CEO is likely to prioritize security and mobile. (The whole "donate to prop 8" thing is a red herring; Mozilla needs…
"Subpar"?
I've used FF on my Android phone for quite a while, and find it nicer than chrome...
[I still try chrome occasionally, "just in case", but always end up ditching it and sticking with FF.]