Hi,
based on the fact, that the iPad Pro's sales numbers could be better and declining iPad (mini/air) sales numbers, Apple has to improve the existing iPad air to keep the buyer's interested.
If the "pro" is of no success it also might get axed sometime down the road. It all comes down to development cost vs. sales numbers.
Based on these facts, Apple might steer the iPad Air product line closer to a smaller iPad pro.
The pencil, the speakers and also the connector are likely candidates to show up in the next gen air.
But what about the price-tag? Well... it's all calculated through accessory. The pencil is about 100 bucks right? So - if you buy the pencil you pay with it for the tech in your iPad. Actually the tech in the iPad is worth only a dollar or two.
Licensing costs for the keyboard dock-connector thingy will also very likely generate money for Apple.
Maybe the device gets a RAM increase, since the iPhone 6s also got one.
I would prefer not having a 4k screen, since it only eats up ram and cpu. The resolution on the air is good enough imo.
bye
Darky