I watch both shows, and enjoy both. I'd certainly say though that Raw entering its Supershow format last year was bad for Smackdown. The brand lines being basically done away with made it to where Smackdown guys can appear on Raw. If we can see people who were originally Smackdown exclusive on Raw then that makes watching Smackdown less of a priority. Say guys like Sheamus, Orton, Del Rio, Barrett, or Big Show were only seen on Smackdown and never on Raw. Would you watch Smackdown to see them? If you can see them on both brands, just about any fan is more likely to watch Raw over Smackdown. Raw was the "A" show and the flagship brand before the Supershow format was even in place, so fans have pretty much always viewed it as more important.
The fact that it's still in taped format does not help either. Raw is live so you do not know what to expect. I watch Smackdown because I enjoy both brands, however I will be completely honest here, I find Raw superior in nearly every category. Smackdown tends to have better matches, but that is it. Raw's Supershow and lack of brand lines have indeed done a number on Smackdown. I won't go as far as to say that it's killing the blue brand, although it's definitely not helping it. Some wrestlers and some Championships should be Smackdown exclusive if they want it to receive more attention. They seem to be content with the way things are going though and fans will continue to remain far more interested in Raw with guys who SHOULD be Smackdown exclusive appearing on both shows. I'm not complaining though, I watch both brands every week anyhow.
"And that's the bottom line, because DAGGER DIAS said so!"