I don't know about The Big Bang Theory anymore. Last night I watched the newest episode and it had what seemed like a 10 minute scene of Sheldon saying "I have wood," when talking about his boardgame, and the other two guys snickered and egged him on. It went on for an unbearable length of time. This is material that, back in the earlier seasons, would have amused one of Penny's idiot boyfriends. Then the smart guys would make a joke about him being a neanderthal because of his idiot jokes. But now they're all idiots, and judging by the enthusiasm of the laugh track, the audience is Penny's old idiot boyfriend.
Raj has been de-empahsized because he doesn't have a girlfriend. All Howard really had going for him was his creepy pickup lines and constant rejection, and Bernadette has killed that. She was good for a few episodes, but now she has been hanging around for way too long.
Same with Amy Farrah Fowler. Actually, I never really liked Amy. Maybe it's because I don't know any girls like that. But I also think her flat line delivery and constant smirking isn't very convincing. None of her lines flow out like they're being naturally said by a person. Apparently she's played by an award-winning actress, but someone told her "walk and talk like a robot" and that's exactly what she does. She needs a different role.