It is evident that the tablet will be quite a bit bigger than the current 9.7" iPad Air 2, but still we can reasonably expect to see again a thin, machined aluminum device, with the general shape and form you would expect from the renowned iPad line of tablets. The sources before pegged the slate's thickness at between 6.9-7.5mm, which is a pretty good achievement, and also confirmed the speculated four built-in speakers.
So far, the rumored specs are for a 12.2" or a 12.9" ultra high-res display, and a souped-up Apple A8 chipset, but the biggest difference might be in the software department. Remember the rumors that iPad Air 2 will feature a split-screen functionality? Well, these didn't materialize for Apple's mainstream tablet edition last year, so it might have been preserved for the more professionally oriented iPad Pro/Plus, or whatever the team from Cupertino decides to name it in the spring, when it is expected to be announced.