Good point with the Air vs Pro. Looks like your extra $200 gets you 2 extra cores plus the Touch Bar and Iris Plus graphics. The Air is there to make the Pro look good value after the upsell though.
There's already Ice Lake 15w parts for an Air refresh where you can choose Iris Graphics (
quad 1.0GHz) or standard Intel HD graphics (
quad 1.6GHz) but all SKUs come with 4 cores and 8 threads.
No sign of 28w parts that would go into a 14" MacBook Pro (not a typo, we're all expecting it

)
For light eSports usage Apple may be able to get away with the Iris Graphics. You're thinking of AAA gaming titles which are obviously non starters for Macs.
I actually think the GPU in the A12X and eventually the A13X would make for a more potent gaming combination.
Clearly there's a variety of keyboard cases for the iPad Pros, but none are backlit and very few include a trackpad (although iPadOS has only rudimentary support for trackpads), nor do they have the amount of adjustability and ease of use that a permanent keyboard might offer to people on the move.
In addition, moving the CPU and SoC away from the screen and possibly giving it a (MacBook class) cooling system could also help with performance over an iPad Pro.
It would also make for a nice proof of concept for a future ARM Mac...