The scene where Bernadette and Amy express romantic infatuation/irrepressible lust for Howard and Sheldon pretty much says that there will be no Penny and Leonard, except tacked on arbitrarily in the last episode, maybe. It's true that you could see Howard/Bernadette and Sheldon/Amy both as tragicomic mesalliance.
Instead, Penny's foolishness about men makes Leonard look like a good catch. Especially since Leonard is the King of Foreplay. Except that women are not supposed to just want sex for pleasure, they only consummate a grand passion when the Power of True Love has melted all barriers, leaving them free to be carried away by an irresistible tide that has nothing, nothing
, to do with lust.
It is unlikely that Chuck Lorre is aiming, consciously or not, at such reality based comedy, he's into farce. Except maybe Raj/Stewart, another pathetic error born of desperation (on both parts.. I'd guess he's distanced enough from homosexuality to take a more dispassionate look.)