We have gotten many amazing movies from the Marvel Cimamatic Universe, but what will happen when all the stars get to old? Evantually Marvel will have to reboot but which Movie will be the last one? By the end The Marvel Cinamatic universe they will have enough continuity to make a movie about...
The Sentry is a Character that requires a lot of continuity! In the comics the Sentry is Marvels biggest gun (slang for the most powerful) and is also a major player in most of the heroes storylines.
How it will help Marvel
1: you can kill or bring back any character you want!
The Sentry powerful enough to match Thor and Hulk, also powerful enough to bring people back to life! You can bring back (spoiler warning, spoiler alert, you have been warned!) that guy that runs fast QuickSilver! Or if RDJ does not want to do Iron Man anymore, just kill him then bring him back for a big event! Screw RDJ out of money!
2: It can explain the disappearance of Fantastic Four, X-men, etc!
In the comics The Sentry is to powerful so he makes everyone forget that he existed! So Marvel can just say that he did it to much or something so that they forgot about The characters they don't own! Or they could say that Sentry killed them and that's why he went into hiding!
3: It will give Hulk another character to let loose on!
The Hulk is running out of guys to hit in the MCU! Wouldn't it be literally the best thing ever to see that Hulk vs Sentry fight from world war Hulk? You don't even have to do World War Hulk (marvel should do it cause it is awsome) you can just have them fight!
4: His solo movie would be an awesome deconstruction of the genre!
The Sentry is a unique character who literally has to fight himself. An alcoholic that became the Sentry because he just need beer. It would Show people uneducated in Comic Books how not all superheroes are the same. It would be just amazing! It would also work as a great Finale to the MCU!