(ON HOLD) Marvel's "WHAT IF...?" Finale Rewrite (by me)

You heard that right, this is a rewrite of Marvel's "WHAT IF...?"
The reason I decided to do it is because I didn't like the execution- almost as fast-paced as the other episodes, and some plotholes such as "why didn't the Watcher help the team throughout the battle against Ultron?"
Hopefully, I don't mess up anything important. :D

"What if..?" and its properties (heroes, villains, background, etc.) all belong to Marvel because of copyright.
This is just a what if. What if...the finale was written differently?