I watched the rest of "Doctor Horrible" and found it to be quite a good critique of the 'Nice Guy' and why he really isn't.
I saw this discussed on Feministe and (my icon aside) I love that take on it. Toward the end I really got the sense he and Hammer were two sides of the same coin. I also like how Whedon acknowledged in an interview/chat that his feelings for Penny aren't based on anything substantial about her.