The Marvel movies have some big short comings even compared to just action films of the Shwarzenegger days. Not old Shwarzenegger, mind you 
As the shared universe keeps clonking on, it reminds me more and more of the Dragonlance prequel novels, or the Star Wars EU books, in which major characters were not allowed to die, or really undergo significant change.
The boring suspense-of-disbelief shattering action, which goes on for far too long and usually everyone comes out of it ok. The CA: Civil War airport scene comes to mind. It reminds me of the Obi Wan vs Anakin fight in Sith because they keep on fighting for so long, that even though eventually they do get to the point of it all, which is the "high ground" part, I'm already worn out.
Why does Loki not die when Hulk flings him around like a sack ? It should break every bone in his body. Is he made of Adamantium ? Then his meat should bleed around those bones.
