I just want to share, in our most recent session, our archer character fired into an empty corridor (illusion) using sound and memory as the only means to aim his bow, in an attempt to hit a black dragon. Rolling two die due to disadvantage he rolled twin 20's. As it happened at that point the dragon had 6 hit points only, which was not nearly enough. It made for quite a great narrative - the archer shooting blindly and slaying the beast.
We have also had our barbarian roll double 1's while having advantage.
So far I have to admit advantage/disadvantage have suited us well. It is a brilliant mechanic and makes for awesome narrative when those doubles appear.