Olivier Vernon is not a very good pass rusher. This should not really be news but for whatever reason a lot of people take a blind eye to what he's actually showing on the football field.
He's good for what he is. He's pretty athletic, and since his days at Miami he's had very powerful hands that allow him to play like a player bigger than his frame would suggest. This is why he's good for base downs, until Dion Jordan is ready to assume the 3-down role for which he was drafted.
But let's not pretend Olivier has a bright future in Miami. That fate was sealed the moment they drafted Dion Jordan all the way up at #3 overall. And if there was any ambiguity, they took that ambiguity away a few days ago by giving Koa Misi a four year contract extension.