Ending Fatigue: Pepper Potts goes up against Christian Grey, awesome, right? He gets his ass kicked, bonus!
...Then he decides to sue Clint and Natasha for their ass-kicking, and goes after Jennifer Walters in the process. Okay, cool! Reading about him get beat up by She-Hulk? Totally worth it.
Then he ends up Amora's champion, going after Jane.
And then he organizes a prison riot, and escapes, during which Rogue absorbs his personality and ends up gong after Clint. And that's not even the end of the fic yet, with it running at 68 chapters. Tell me, why haven't they killed him already, again?
Interestingly, the ending fatigue basically is the reason the fanfiction becomes a full-fledged story. While the subsequent sections drag out the initial point of the fanfiction, they're treated more like subsequent episodes.
The fic not only predicted the appearance of the Winter Soldier in the MCU, but gives him the name American Sniper.
In the fic, Hawkeye has such a low sperm count that he's thrilled to have been able to father even one child. In Age of Ultron, he has two children and his wife is pregnant with a third.
Harsher in Hindsight: Widow's worries over her prior miscarriage, and worry over whether she should have Hawkeye's kid are this in light of Age of Ultron revealing that her Red Room training made it so she can never have children.