I have been a fan of this show since the very beginning but I must say not only has the writing become stale but the tried and tested formula of adding gf's for the various characters has been for the most part a complete flop. I particularly detest Amy Fowler as Sheldon's girlfriend. She is utterly painful to watch. I think the fundamental problem is that she is too like Sheldon albeit with a layer of juvenile sexual confusion. She is simply not funny nor particularly believable. She is really nothing more than a clown. Sheldon needs a foil not a reflection. Why not hook him up with a hippy humanities chick? Opposites attract but more vitally conflict opens the door to genuine humor.
In the same light Howard was far more interesting as a guy on the prowl rather than as a person in a stultifying relationship with Bernadette. I cannot recall one funny scene with the two of them. Bland and banal comes to mind. ( Simon Helberg is actually one of the strongest actors on the show; he is quite brilliant.)
Sorry but unless the show improves dramatically I will recall it has having three good seasons, the first two being very strong. The rest is lapsing into nonsense or vapid predictability.