If they can fit a 5.5" display into the current 4.7" iPhone form factor, then what's to stop them from putting a 6.5" display into the current 5.5" iPhone form factor? At that point you're almost iPad Mini.
What I'd really like to see is some differentiation. 10.5" seems to close to 9.7". Maybe they could knock the 9.7" cheaper model down to 9" with a reduced bezel and it would be close enough to the size of the iPad Mini? The main issue here is the PPI. The 10.5" iPad makes sense because it's supposedly the same resolution as the 12.9" but at 326ppi instead of 264ppi. It's basically what Apple did with the iPad Mini when it had the same resolution as the iPad but at 326ppi instead of 264ppi.
I hope the new Pros come out at WWDC. I'm not holding my breath, but if they do it at WWDC I'm hoping they're going to show off a redesigned iPad iOS that makes it a lot easier to get work done on the device. I decided to hold out for gen 2 of the iPad Pro due to the 2GB of RAM, which seemed like it would become outdated with Pro apps rather quickly. I also figured it would give more time for Pro apps to come on the market, but that is questionable. At least a lot of apps support Apple Pencil now, which is the main reason I want one. Hopefully it can be used as a drawing tablet with the Mac.