Willian is certainly not the worst player in the world, but we really should stop picking up people who Chelsea can't be bothered to keep. Anyone who spends the better part of a decade playing for them better be world class if they expect to be welcome here.
Added to that he's old as fuck and we already have plenty of players on the wings. Which means he's probably intended as an experienced replacement for someone, and you don't have to be a genius to realise that someone is probably our best player, the bloke who hasn't signed a contract extension yet and now has less than a year left on his current deal since we passed into July.
Replacing Aubameyang with Willian is the sort of move that, should it materialise, I hope motivates the fans to pick up literal pitchforks and drive the entire Arsenal board into the sea.