Most photographs have been printed on paper that is closer to the 4:3 ratio than 2:3. I personaly find the 2:3 format awkward, always have. Especially for verticals.

Portrait photographers will probably embrace the 4:3 like they did the 645 format. Same for commercial shooters, who have to fit magazine page layouts.

But for the artsy types, I suppose any format is just fine. You learn to work with it.