IMO Apple had struck gold in coming up with the 9.7" size for the iPad and the 7.9" size for the mini. Disappointed Apple decided to increase the screen size.
Do you guys see Apple again changing, coming up with a new screen size in the future ? or it will stick to the 10.5" screen size for future iterations now ?
The 9.7" display is from a bygone era of "the iPad is just a bigger iPhone or iPod."
Today, the 10.5 and 12.9" iPad Pro is positioned as a productivity device.
Apple itself never made a 9.7" MacBook Air. The smallest one Apple made was the 11" MacBook Air - and that model has been discontinued. That tells you what Apple thinks the smallest display should be and still offer productivity value for the user. Even the cheapest netbooks today have an 11" display. If you spend $400, you can buy a notebook with a 14" FHD display.
If Apple can squeeze an 11" or 12" display into a 1 lb chassis in the next few years, I would expect that to be the next standard for iPad Pro.