Just trying to imagine actually drawing on the smaller iPad....I like the true tone feature, but I like the screen real estate of the larger version (not so much the weight). Also the cameras don't matter, and yet I'm still struggling to decide between the two.
My case is kinda funny. I was long time wanting iPad which works with like Apple Pencil. When iPad Pro 12.9" came out, I was hesitated until very last moment just before the reservation started after midnight.
Only reason I was interested into getting 12,9" Pro was Apple Pencil, and I wished if it's bit smaller like 9.7".
After I picked mine up on the day of it came out, first my impression was "Geez it's HUGE!"
After few days of use of it, I completely understood, why that size was set as 12.9". That was just the right and comfortable size to draw. You don't need to pinch and spread and that's actually similar to usual paper size.
And split screen mode is convenient. I sometimes draw by watching pictures as reference. And then I use split screen mode, half size of 12.9" is almost equal as iPad mini screen size. It's smaller than 12.9" of curse, but yet workable for short time.
I also compose music on my iPad Pro. Many of those Apps actually much easier to operate on bigger working space.
When 9.7" Pro was announced, I went to go to Apple Store to check how 9.7" iPad size look like, since only another iPad I ever have was iPad mini 4.
It just didn't look like comfortable size to work on drawings to me. And split screen mode totally seemed not usable, just because half of 9.7" screen size is too small.
Although I didn't get 9.7" Pro, if next iPad mini will be released with Apple Pencil support, then I'll buy it.
For me, 9.7" is still big as to go device anyway, carrying 12.9" isn't much different(especially because I don't use attachable keyboard). If both devices anyway can't be so comfortably mobile, I don't have any reason to get 9.7", it seemed 12.9" fit my needs better.
I don't need better camera, I don't take pictures on my iPad and anyway cell phones have much better quality of cameras nowadays.
I don't want true tone display, I want consistent color when I work on digital drawings/edit photos.
So, I decided to stay with 12.9".
I think it totally depends on what that person wants to use it for. 9.7" Pro isn't for everyone, so as 12.9" Pro, and iPad mini.