I agree so much with you. If a majority of the season isn't what you're hoping it will be STOP WATCHING. I did that with Smallville. Season seven failed miserably, save for like one episode, so I no longer watch the new episodes.
I love where Who is going personally, but that's probably because I know that in the end it's a television series and it's purely for entertainment. When it stops being so, that means it's time to change the channel.