Honestly, I'm not a big fan of Seth Rogen. That's not to say I dislike the guy or anything ... I just think he hit too big, too fast before developing the skills needed to fully anchor a film. He followed a short string of hits with a short string of flops, and it's kind of unclear exactly where his career is headed next.
His role in The Green Hornet just makes things that much more confusing, but I wish him the best... Rogen starring in a superhero film is no less crazy than casting Michael Keaton as Batman. (And certainly more reasonable than an idea I had back in 1988 to cast Tony Danza as The Punisher. Don't ask.)