I feel like I am Team "Imitation Isn't Acting"...I thought Jamie Foxx as Ray Charles, Joaquin Phoenix as Johnny Cash, PSH as Truman Capote and Meryl Streep as Julia Childs were all terribly overrated performances. I did however really like Malek's Freddie Mercury.
To be honest, I have very little by way of reference point on how Charles, Cash, Capote, Childs OR Mercury moved and spoke. So it would be hard for me to like or not like them based on the degree of accuracy. I think even without that reference point one can sense a lack of authenticity (a matter of opinion to be sure, I might not see it where others do).
So even if the actor nailed the imitation, I might find it too big, too over the top and generally off-putting. I'm not sure if that is on me at that point or if the actor holds a responsibility to find the balance, even it it means compromising the accuracy. I felt the real person, the depth to Malek's Mercury. Other than the teeth thing there wasn't a lot that felt particularly mannered to me.