Superman is largely invincible, yes. He does have well known weaknesses (Kryptonite, red sun radiation). Over the years he has crept up in his power levels so DC has a 'Crisis' where everything gets rebooted and he's suddenly less powerful.

Wonder Woman used to be a somewhat above average, albeit ageless, human who was highly skilled and had magical weapons. If you shot her, it'd hurt or possibly kill her. She has magical bracelets that are unbreakable so she would block bullets with them.

These came with a catch. The bracelets were a symbol of the Amazon's enslavement by Hercules. If those bracelets were linked together then she would lose her strength and become weak. This weakness has been excised from existence.

Then there's the lasso. It's also magical and also unbreakable and can force anyone restrained with it to tell the truth. It also came with a catch, if Wonder Woman herself were restrained with it then she would become powerless. Again, excised.

Oh, and remember how I said she had to deflect bullets? Not anymore. She's now basically Superman with absolutely no weaknesses. Also, I forgot, she's also the finest martial artist in the DC universe.

And let's not even get into the more concerning aspects of her personality. She's supposedly an envoy of peace and love from her people to "man's world". A job she earned by being the best at fighting amongst a race of women who do nothing but train how to fight all day. A race of women who killed boys in the street for being male.

So, her suddenly appearing and beating up Doomsday for the movie's actual protagonists is a huge concern for the future of this franchise.

Sure, the part where she blocks Doomsday's heat vision with her shield and her theme plays was pretty cool but as soon as a movie about Batman and Superman turns into Wonder Woman shoving the boys aside so the girl can look cool, I start to have my concerns.

Suppose in her movie, Martian Manhunter shows up and beats up the villain for her. He's a million times more popular than she is but would people tolerate that? I doubt it.

I'm not the best judge as I'm a heterosexual male, but is Superman not hot? I think it's fairly sexist to deflect criticism of a character by saying 'well the actress is hot'.