How is it overloading? Dr strange will be nothing like any previous movie, ant man might have elements from say iron man and perhaps new cap america as far as action ad sequences go. Thor is its own thing, guardians of the galaxy is their Star Wars in a sense..
MCU is great. Original and fresh and as long as they keep hiring good actors and directors while having good scripts, how can anyone complain? Enjoy it while it lasts I say. By 2017 we'd have seen
Iron Man
The Incredible Hulk
Iron Man 2
Thor
Captain America: The First Avenger
The Avengers
Iron Man 3
Thor: The Dark World
Captain America: The Winter Soldier
Guardians Of The Galaxy
The Avengers: Age Of Ultron
Ant-Man
Dr. Strange: Sorceror Supreme (announced by Feige but not officially)
Black Panther (rumour)
Thor 3 (all but guaranteed)
Captain America 3 (all but guaranteed)
The Indestructible Hulk (rumour)
The Avengers 3
Because it's over-saturation. There's no need for so many superhero movies and they are beginning to become repetitive. As of now only Iron Man and The Avengers of those listed can say they are great superhero movies. The rest are average.
On top of those we have more X-Men movies and a needless Spiderman reboot. Then on the other side we have yet another Batman reboot and a completely rushed DC universe to try and compete with Marvel.
And I wouldn't call it original and fresh.