Adult superhero movies is a phrase commonly used with many comic films though not the MCU movies.
Can I also remind you DC already has an animated TV line that appeals mostly to adults? the recent ongoing Harley Quinn series?
I don't agree with this. I think anyone who saw and loved the feel good fantasy of Reeves would be more accepting of Man of Steel because of age and time. It was all about story evolution. I only wished Man of Steel had come out in 2008 or 2009 not in 2013.
Superman Returns was a good bridge between Superman 2 and Man of Steel. The superficial complaints of man of steel would have been less if some people for once had stopped using Avengers 2012 as a ''good example'' for a Superman movie to follow.
Christopher Nolan even said in interviews that Man of Steel was not trying to be Avengers, shame some did not listen.