Well I loved parts of this episode. The meat of the episode was very strong, too bad it was tops 10 minutes.
As for the TV spoofs, well two I found laugh out loud funny. Herplexia, and Night Rider (And look get another slash reference as Dean is fisting Sam, Yikes). Those were the only two that stood up fully in the humor department.
The opening credits had a few montage scenes that I enjoyed, there were a few pointed moments at Grey's that I enjoyed, and I liked the Hulk.
As a metaphor for the state of television, I actually found Ghostfacers to be the stronger outing, hell even Hollywood Babylon's attack on studio management was better. But both of those lacked this episodes stronger undercurrent.
What is interesting is so far the two times the show has truly retcon a plot point, both have worked really well. Trickster being an Angel and Azazel's true plan being raising Lucifer.
And I found the casting and the acting to be really weak (which was probably intentional) for the most of the "Shows" segments, and the only segment that fell completely flat to me was the spoof of Japanese game shows, which tragically even The Amazing Race did better on the fly then SN did.
But this was clearly the Tricksters best performance. He did really well. But his lesson to Sam in the 3rd season seems off base now. If he truly believed this is fate, or destiny without any hope of change or free will, why the warning to Sam to just let Dean go. To not obsess. That doesn't track. Now if he was just wanting Sam to let Dean die (to let Dean start the chain of events), you would have thought he would have encouraged Sam's darker impulses, not tried to warn him away from them.