I went from a road bike to a mountain bike and back to a road bike after many years. It's daunting the second time around too but you get used to it and it my case I now prefer it.

The extra torque you get from flats is because they're wider. The torque is helpful for navigating over rocks, roots, logs, holes, etc you encounter while riding off road. I can't think of any situation in my commute where I wished I'd had more torque ;-)

The extra width can be a downside in city riding because now you've got less clearance between you and the other vehicles around you. May not make much difference in practice but really narrow bars are getting popular with the fixed gear and SS crowd for that reason.

Having all the controls at your finger tips is a real advantage to flats but that's due to the fact that there's really only one spot for your hands. As soon as you put bar ends on the advantage goes away. t With drops you've got good access to controls in two positions, and at least brake control in three with cross levers. At worst, it's a matter of moving your hand a few inches.