To take it another step (since I didn’t get a chance to point out those things last night, but you are absolutely spot on), look at the 3 most prominent figures, and their relative sizes. It starts in the upper left with Kylo, and his is the largest, but there is a straight line diagonally to the middle right that goes from him, through Rey, to Finn. Each progressively a little smaller. So naturally your eye is drawn from Kylo to Rey, then Finn with the lightsaber.
Another is eye focus. There is a strict median on the poster. Characters whose faces are to the right half, are all looking right. Those on the left all looking left. This subtly adds to the idea that the conflict is larger than what is shown, that there are larger outside forces acting.
Compare that to this poster
They are all looking inward, and perspective puts them into the distance. This tells a story, and shows that this is primarially a conflict between these individuals, and in this internal fight the primary actors are Captain America and Iron Man.
The Spider-Man poster has no such focus. It is a hodgepodge of elements that tell no story, have no perspective, and say nothing together. Why is Iron Man the most foreground element, Spiderman the most background. What is Tony looking at? Why half NYC and half DC? Is the Washington Monument there for any reason? Just have the Stark Tower and be done.