Out of curiosity, why doesn't a powered Thunderbolt dock solve that problem for you? I went from a Mac mini to a (generally docked) MacBook Air, and that setup has worked great.
Oh, and they cost $150 to $250. After shelling out for a new computer, I don't want to spend hundreds more to have access to functionality that was included with every new MBP (and even some MBAs!) seven years ago.
The only thing that dicks me with the MBA is the shitty webcam. Even the base 9th gen iPad has a decent front camera. I use my iPad Pro 11 for that instead though.
The mediocre webcam doesn't bother me that much, but I do wish Apple made it easy to use your iPhone's back-side camera for video conferencing. Seems like it would be so easy, and then you could use all the bokeh effects and such.
The main downsides of the the MBP for me are: (1) it will cost more, (2) AppleCare will cost more, and (3) it will be somewhat heavier.
But for extra USB ports and an SD card slot, I'll take it.