This is the word of the hill-lessMy Best Mate is a un-recoverable Roadie Wanker and buys a road bike every 18 months that makes my Procaliber look cheap. So in my experience, early versions were horrible with a huge lever throw, and light switch modulation. Back then I much preferred the old cable brakes. I've not ridden a modern set in anger, but the driveway test has proven they've come a long long way.
Plus the UCI thing, and the whole traditional 'I don't need technology because I'm a Roadie and therefore I'm a man' mentality. If the peloton doesn't want it, it won't happen. Same as you'll never see a compact gear ratio set in The Tour.
These days every mainstream manufacturer (Trek, Dale, Spesh) has gone disc. They've discovered the MAMILS have the expendable cash, and the technology trail is starting to flow in the other direction. The MAMILS are starting to realise thru-axles are a good thing, and maybe the traditional ways maybe aren't the best way.
I reckon I've seen on this forum someone has swapped in M-8020 four pots on their roadie