Why don't ADCs take exhaust more often?
I'm pretty low elo ATM (high plat low emerald) but I've found on lower range ADCs like Lucian, Sivir or Vayne that exhaust has a lot of mileage. It gives you a pretty potent CC on top of excellent duelling power, and is way more efficient than barrier for shutting down divers and assassins after lane.
I get barrier is much easier to use and can save you from mages early on, but I feel like positioning is much more important for that anyway. In an all in 2v2 an exhaust on the other adc is generally a lot more powerful than barrier too.