Yes the show has changed but in a good way.
I've always related to all the geeks (mostly Lenard and Rajesh) on some level. I'm a shy guy that has always been involved in really geeky stuff (501st, star wars.. I work in IT ..) My life was similar to theirs, doing geeky crap cuz screw everyone im going to do it.
Well now I have a great girlfriend like many of the guys on the show, and know what. Things change you stop doing 'halo night' and hang out with your girl instead. So I can relate and it shows the characters are evolving. They are still the geeks we love, but their lives are changing as most geeks do. Its a show that for the risk of looking corny, has given many of us hope.