It would be wiser be for shimano to priorotize development/release of a 105/tiagra level Hydraulic disc/Mechanical gear actuating STI in a lower price bracket to attract more MAMILS, commuters and CX riders, obviously their mechanical disc calipers already cater for that market to a certain extent already but affordable hydraulics without Di2 might drive adoption better than expensive bling.
Shimano are in danger of missing several boats IMO by not putting together a few of their key technologies in the right sort of packages and price brackets in time to corner some key markets...
Drop bar'd commuting and touring is a peculiar british thing, the rest of the world does it on flat bars.
I'd say Ultegra is the perfect level to pitch it at, the pro's (DA) don't want it, the proles (<105) can't afford it, MAMIL's with more money than sense will lap it up.
I have - the rear wheel blew up on my road bike due to the rim wearing through.
I got close once, but they usually seem to suffer a ding from a missed pothole, or just go out of true once too often.
so that'll be £90 on rims, plus spokes (£60?), plus building (£50?), in my near future.
Even if you did pay that much (I paid half that for spokes, rims cost whatever you want to spend, and building yourself isn't beyond anyone with fingers and a brain), then that's still 6 years (or 12 if you can build yourself and don't pay over the odds for spokes) to pay off the brakes. Assuming the disks last that long, my first shimano brakes lasted 8 years before a seal went, and that's without road salt/grime attaching them, and the braking surface of ice tech rotors is seriously thin and they're £50 an end (so more than rims!).