As to the quality of this poster. Part of the process when creating a poster for any kind of campaign is creating a number of different rough sketches to show your client.

It would not surprise me to learn that this was one of the alternates that Struzan threw together just to give them options. Not knowing that they'd end up commissioning at least two posters. This one being for promotional purposes at D23.

Another thing to keep in mind is that he's at the mercy of his client. He very well could have had something else in mind for the bottom of the poster but then was requested to toss Solo in there after the tremendous response to the ending of the first teaser.