The rumor mill isn't making much noise about iPad Pros, but I really hope there is an update.
In addition to the chips and RAM, the iPhone can even match the iPad Pro's storage capacity (256GB). More space is always desirable.
I would really appreciate a waterproof (or resistant) iPad Pro. Now that the phones have it, and considering the ASK is waterproof, it just seems the logical next step to me. Using the iPad Pro as a reader, for me there are so many situations in which I'm touching it with wet hands (condensation from iced drinks, a walk in the rain, having just washed hands, etc.)...the peace of mind would really be nice.
And systemwide handwriting recognition as a form of input using the Pencil would be nice, since Apple clearly has the technological capacity to do this as demonstrated on the Apple Watch (which is a less powerful device)...
New home button and haptic feedback to match the phones is also missing...
Apple Pencil 2.0 could charge wirelessly in a dock of some kind and be water resistant as well.
There's a lot that can be done for these devices...they're far from perfect or in a state in which no improvements are imaginable. The question is when, and I hope soon!