Regarding Tracer
And it takes loads of skill to pull off correctly.
Regarding D.Va
Yes, you are correct, But That is not nearly as hard to do as getting a Blink Melee without overshooting or undershooting your opponent.
Regarding Genji
Ah. when did they fix that? I just used it like, what seems like just yesterday. (it was probably months ago, because I have not played Genji in a long time.)