I'm wondering when either group set will actually be available for purchase
and delivery. One video stated, "You *should* be able to buy bikes with the new Dura Ace right now." I'd be surprised if the average person (in the USA) will be able to get their hands on these group sets before 2023 with all the inventory issues currently going on. I'm sure you'll be able to place an order for a bike or the group sets right now, but who knows when you'll actually get either.
That aside, I like all the incremental refinements that appear to be in the new group sets. In the 25+ years I've been riding Shimano, each new group set has been "just a little better" than the last and the 12 speed groups appear to continue that tradition. I'm fine with the mechanical group sets going away, but I'd have to think that'll leave quite a price gap between a mechanical 105 equipped bike and an Ultegra Di2 equipped bike unless Shimano radically drops the price of the new Di2 (not holding my breath on that!)
This video helped me understand some of the design decisions in the new group sets, such as the symmetrical crank design, the larger brake levers, mountain bike calipers, etc.: