Yes, all the movies you listed were pretty bad. Even as a kid I thought there was something missing from the Supergirl film.
I think this may have a little to do with that there are apparently too few actresses that can play tough and beautiful. (Does she have to be beautiful...I don't think so, but Hollywood sure does) I want to see more female heroes on the screen, but since it appears casting is ALL about the TnA maybe that's part of the problem. I won't deny that 'curves' sell movie tickets - but we all know that's not all female comic heroes have to offer.
Who will have the stones (lol) to make a movie about a female super hero and DARE to not make it ALL about the spandex, high-heels and cleavage? Maybe the public will take female heroes seriously and clamor for more! I would.