When I'm running the MBA closed, I use a Magic Trackpad – it's much easier on my hand than a mouse. I'm hoping I could adjust to the larger trackpad more easily because of that? Dan, have you ever used a Magic Trackpad? Of course, that set-up puts the trackpad next to the keyboard, not below it.
I had 15" MBP before the Air. I have liked lighter and thinner. At this point, however, the two 13" machines weigh pretty close to the same (Air = 2.96 lbs; Pro 3.02 lbs), so weight is no longer an issue like it was when I bought my Air. Size-wise, they're also close to the same, though slightly different profiles – a non-issue. The Pro specs are much better, and the price is considerably higher.
I can see little point in moving to an upgraded Air. I'll either stay with what I have a little longer or buy a Pro.
Mark – Your review is very helpful. Do you think that putting a Touch Bar in a bluetooth keyboard would not work because of the power required to run it? (I'm finding myself wanting to go back to a more powerful machine rather than sticking with a less powerful one even if it is less expensive.)