It would be really embarrassing if they didn't revert. I'm in.
Not me. It's hideous.
You're in agreement with the parent comment. "Who's in?" means, "Who's in on the bet that they will revert the logo [because it's hideous]?" (We're all in agreement, of course. This new logo is the seventeenth sign of the Apocalypse.)
I read that he wanted someone to take the bet with. As in he wanted someone who disagreed so they could stake money on the outcome.