This is starting to sound to me like you guys don't have any idea what you're talking about. Have you ridden modern hydraulic road discs?
Around here our mtb trails are wet roots and mud, there's no traction and yet we must brake to keep the speed down.
There is way more grip on the road on a road bike than any mtb where your speed is literally limited by your ability to brake. Modulation is the name of the game in mtb and my road discs are just as good - perfect control from the hoods with 2 fingers of force.
I had r785 shifters but I hated the shape of the hoods. Upgraded to r8100 and they're perfect for my hands.
I am wary of the unrepairable clockwork complexity in all the brifters but the hydraulics have been bombproof.