Its very straightforward. AFAIK (and IANAL, so take this with a GOS*), you don't get to change your argument on appeal; you have to make an argument that the judge was wrong. So, the appeal will likely be denied out of hand.
Sentence two is spot on. Judges in my experience don’t like to rock the boat by criticising their own, but interpretation of
fair use is the crux of this case. Appeals
do get over the line, in many jurisdictions. But changing horses in mid-stream is not going to impress.
Still, I suspect that a lot more people have heard of Cariou now than would have without Prince's infringement. Food for thought.
And I don’t see how Cariou has suffered
any harm to his business or reputation. As you state, more people have heard of him
because of this case. Here is a
link to the photograph and the copied sculpture in the Rogers v. Koons case. Rogers [photographer] was successful in that action.
This will be an important and influential ruling. One observation I have is that Prince was very dismissive of Cariou’s work (“…
mere compilations of facts …
arranged with minimum creativity”) in the lower court; so why did he use them?
IANAL?