I think there is another advantage (to merely having the white keys) besides just transposing being easier. And this is that the same intervals will always have the same spacing on the keyboard. I guess this should be my main argument for this type of layout being more natural.
Yes, they would be the same spacing, but that spacing would be extremely uncomfortable and lots of pieces would become impossible to play. Making the black keys the same size as the white keys, a 8th would become a 13th. I don't have small hands and I can barely reach a 11th interval. Basically, a lot of simultaneous notes could no longer be played. A solution would be to make the keys smaller, but then you wouldn't be able to play semitones because your fingers wouldn't fit comfortably. To fix that, you could raise some keys, so basically you would end up with the current setup.
Good points. But I really don't understand why the keys need to be that big. People are used to typing on smartphones, where the sensitive area of a key is like 30% of the width of a finger. Of course, making them that small would be a little extreme, but I think piano keys could be much slimmer.
Have you seen anyone try to type on a smartphone? Slow, and riddled with typos. Keep piano keys the width they are, unless you want slow, error prone pianists.
Besides, we already have the ideal chromatic keyboard layout:
I think there is another advantage (to merely having the white keys) besides just transposing being easier. And this is that the same intervals will always have the same spacing on the keyboard. I guess this should be my main argument for this type of layout being more natural.