"iPad Air Pro" is getting too far into Microsoftian territory for naming an Apple product. But here's the thing, Apple already has multiple products with the same name: 11" MacBook Air, 13" MacBook Air. 13" MacBook Pro, 15" MacBook Pro.
What we are seeing here is that if the rumors are true, Apple is going towards a similar split on their iPads: 8" iPad, 10" iPad. 10" iPad Pro, 13" iPad Pro. The naming mess in the short term is more not wanting to rename / rebrand a particular model during it's lifecycle. Again, assuming the rumors are true, I'm going to start expecting that the 8/10" iPads will get updated at the same time, with the same specs, and the 10"/13" Pros will get updated at the same time with the same specs. And much like the MacBook / MacBook Pro split, the "Pro" line will represent more connectivity, higher end specs, and higher cost.