iPads need wider screens... They absolutely suck for watching movies or other video content thats shot in 16:9 aspect ratio. Your 9.7" screen becomes like 7" because all you see is black bars...
Sorry but that will never happen!
4:3 aspect ratio is way better for things like Web browsing, Gaming, Reading ,Productivity(office, video editing) and lots more and 16:10 and 16:9 aspect ratio is only good for watching videos/movies and not so good anything else!!
You do realize lots of people use tablets for lot other stuff than watching videos/movies, 4:3 is becoming the new standard for tablets look at Google and Samsung they have all changed to 4:3 aspect ratios from 16:10, 16:9 on there tablets(Nexus 9, Tab S2, Tab A) because they realized now that the 4:3 ratio is a way better format for tablets then 16:10, 16:9.
So if your main use for tablet is to watch videos/movies then get a 16:10, 16:9 Android tablet or Windows tablet!!
Apple have a very good reason why they should stay with 4:3 on there Ipads rather than changing to 16:10, 16:9.
But i do think Apple should try the 3:2 aspect ratio(like on Surface Pro 3) on there ipads especailly on the rumoured 12.9 inch Ipad Pro in the future!!