I view TBBT as a mixed bag, and everything that is wrong with network sitcoms. It's no doubt funny, and my daughter and I would watch it together (so it was special that way), but inevitably, as the characters have to grow, they lose what made them special to begin with. Raj is BORING once he started to talk. Sheldon is BORING "exploring his feelings". Penny is still hot, but BORING as she turns from the cute, easy "actress" (read: "waitress") into the successful pharamceutical business woman wife. Leonard is BORING and annoying with his insecurities while married to the hottie across the hall. Wolowitz is BORING as he turns from pathetic loser letch into a walking Borscht Belt comedian with the brisket jokes, etc. etc. That show, like M*A*S*H before it, was awesome sauce for two maybe three seasons, and when they started to "humanize" the characaters, pffffft. Doesn't mean it wasn't funny at times, but it wasn't the same.
Call me a curmudgeon, but while the very last episode was better than it could have been, I'm not one of those that gets any satisfaction or "closure" out of happy endings for the characters, especially if, like MirrorMask so correctly points out, there are such gaping holes in the premise. (My son is on the spectrum, and he might as well be Sheldon, without the neatness, arrogance and the discipline. Every time Sheldon expresses his love of trains, it almost makes me dizzy with deja vu.)