12. The Incredible Hulk

As said, The Incredible Hulk has received the poorest reviews and we don't see that changing in the near future. And, for the better part of it, it doesn't seem at all like an MCU movie. If it weren't for this year's Civil War, there would have been even less of a connection to the larger shared universe.

The Incredible Hulk feels very generic, even if some (including myself) believe that Edward Norton shouldn't have been replaced by Mark Ruffalo. Even if it aimed to be the most emotional of the lot, it has also failed, because of the lack of chemistry between the leads.

That being said, the Incredible Hulk did let the Abomination live in the end, so we might see some showdown between the Jade Giant and his enemy sometime in the future. I wouldn't bet on it, though, since Hulk isn't bankable at all, and he works better (for the box office results) when co-starring with other Avengers.