Big Bang Theory, what's happen to the show?

I watched the latest episode this week season 8 episode 16 (The intimacy acceleration) for me the show reached a new low point.   The latest series has struggled to find it's way from the beginning. 
 I think the series has lost it's original concept of a few geeky guys trying to find their way in life, the characters have changed hugely since the original pilot episode, before it was just about believable, now it's just silly.  You have Penny the dumb waitress now working in a powerful job and getting smarter with every episode. Howards married someone who sounds exactly like his mother, Leonard and Penny seem to be set on getting married. Raj seems to be the comic relief with a smaller and smaller part all the time, come on guys get back to your roots!
 As I mentioned earlier the show hit a new low point this week with the cast using the loss of Howards mother Debbie Walowitz ashes at an airport, I say new low point because the actress who played her died in real life in November last year (Carol Ann Susi age 61) in last weeks episode the cast made a nice gesture to Howards mothers death, then just a week later use it for a bit of weak comedy. Tasteless and unnecessary.
 The show just isn't funny any more, and it seems I'm not alone in saying that.