That's an interesting point I hadn't thought far enough ahead about. I've been captivated by the idea of an black alternative shoe and was coming around to the idea of gray. Not gray, gray - but rather something subtlely not jet black, like these with the gray "cloud". It hadn't occurred to me how it will wear over time as it gets worn and I think you're right, it will end up looking mottled and probably not attractive.
Maybe I really should be looking for something more matte, or even a plain "charcoal" instead. Hmmm...
I do have to say it is a brave attempt to mimic JL's museum finish and from what I've seen i just needs to have a deeper finish, darker, and have more gloss.
If I had room to spare I'd pick the PA and see how it would patina.
The PA color is pretty close to a pair of boots I have: