Never said anything about you, I said "people", and there are a couple of people with this specific expectation…
"1.6x improvement in animations and scrolling", not 1.6x smoother.
Some forum-goers said Control Center scrolling used to be 60fps on 8.4.1, so going by "smoother", what is the expected result? 96fps?
Improvement can mean so many things in this context—CPU usage, energy efficiency, etc. (or a combination)
Also, Metal did improve graphics performance in e.g. games.
Bugs? Feel free to add them to the wiki on the first post. Thanks.
Whose to say they never tried fixing it?