Regardling 32" winning Unbound...it will be interesting to see how much buy-in there is for 32" gravel wheels and tires. Right now, 32" tires are all in traditionally MTB widths.
How much actual interest is there for a 45mm 32" gravel tire? How much adoption will be just sort of inevitable due to that is what some well regarded bikes are designed around, and that 'buy-in' then snowballs?

Geometry, at least on the smaller end, will be fascinating. Over on paceline, David Kirk has written about this and the design concerns/challenges are really interesting.
I am 6'5 and am not concerned about a 32" wheel gravel bike fitting me properly. But my youngest kid who is 5'3?...that seems like an issue, at least at first blush.