Air will probably have 4GB RAM, which will be ok for the Air. The 2018 Pro’s had that and they are very capable. But the thing is, the base storage for a device like the Air should be 128GB. 64 is not enough and is a mismatch for the feature set.
This means you are going to have to go with 256GB if you choose the Air, and then the price difference between the Base model 128GB 11” Pro and the 256GB Air is only $50.
I have the 1TB 2018 11” Pro, and have it loaded up good, and am currently using 132GB only. That is fully iCloud sync’ed including 50k photos and videos as well as iMessage media, iCloud Drive, etc. with iCloud storage optimization turned on, but not using the Offload unused apps feature. A quick look tells me I could save 44GB or so by using this feature.
On my 128GB mini 4 I restored it from my 11” Pro backup, so it is identical with identical apps and device/iCloud settings, and it uses 85GB right now. Difference being that iCloud Storage Optimization keeps a healthy amount of headroom.
So I could definitely live with 128GB, but definitely not live with 64GB. I tend to think that the majority of users who use their iPad as a primary portable personal computing device (say instead of a personal laptop, but not instead of a personal desktop) or as a media and content hub for consumption and lighter editing and creation would fall under this category.
Heavier users that want media stored locally on device would need more, at least 256GB if not more. I find that 256GB is a bit cramped on my Macs, but have never even really had to think about storage on my iPads after going 128GB+ on them since the first iPad Air.
My point is this. How compelling an argument can you make for the iPad Air when it is so close in price to the base Pro when you account for having to go for the higher storage on the Air? I mean, for me, the 120Hz Pro Motion screen, 2GB RAM, and A12Z is not worth $200, but it probably is worth $50?
Hard one! Interesting how hard they make the choice, because they really probably originally planned to not leave the Air hovering that close to the Pro for very long. I honestly think that they were going to release this in October with the Apple Silicon Macbook(s) but then had to swap them with the iPhone when it became clear they weren’t going to make the window for the iPhone. I mean the Air isn’t shipping until October either!