I thought about how I would structure phase 1.

Captain America: The First Avenger. I think that the subtitle should be dropped as we learn the names origin in Captain Marvel.

Mid Credits: Steve waking up in 2010

Post Credits: original scene with Nick Fury.

Post Credits: Ivan Vanko building an arc reactor.

Iron Man 2. I think that a new title should be added as a subtitle, as I’ve never liked how the iron man movies were numbered.

Mid credits: Coulson’s one shot.

Post credits: Coulson finding Thor’s hammer.

Post credits: I’m not sure what to put here.

Mid credits: the cat vomiting the Tesseract.

Post Credits: Nick Fury recruiting Dr. Selvig
7. The Avengers

Mid Credits: Shwarma

Post credits: Thanos tease

I have multiple reasons I think this ordering would be effective;

The focus of phase 1 should be the Tesseract. Introduced in Captain America, it would return in Captain Marvel. In the Avengers the other heroes deal with it too.
Coulson’s journey. His sacrifice is very important to the formation of the Avengers, and I think should be highlighted throughout. In iron man we meet him as a government agent. In Iron Man 2 his competency is shown and he gains more character. In Thor we see his heart and his inert goodness. Then, we travel back to the 90’s where we see his goodness displayed once again, and we learn why Fury trusts him. His sacrifice is more effective this way I think.
As many have said, the Incredible Hulk is a better movie when placed after the first Captain America movie. It shows what they were trying to create, a new Captain America.

Those are just a few ideas.