Ke$ha will definitely be big next year, her songs are very radio-friendly. I honestly don't know what people are hearing when they say it all sounds alike, "Tik Tok" is similar to "Blah Blah Blah" but that's about the only direct similarity I hear since most of the album is not even the same genre as those.
And the live performance aspect is irrelevant since there have been lots of stars who have made it big without a stand-out performance. It's not as if she can't sing either, I've seen her perform "Tik Tok" live and she sounded good so she doesn't have to depend on autotune.