"Powered by"
should be in the language file (agree with Zarzal lol) because in another language people might not understand what it means. Those two words have nothing to do with the copyright statement, but help them understand that it
is a copyright.
I liked the old hover-over for the version number in 7.1, not sure if search engines would see it or not? It's good to know the version number another site is using if trying to debug or answer their questions, or answer our own questions...

But I do get the possible security issue if a particular version might be exploitable...