Good players will eventually find a way to score or produce ie. Hall.
Drouin is a fantastic player, but his attitude is terrible. Watching a few Habs games and seeing him sulk when the play or puck does not work in his favor. He acted in a similar manner with TB. Not sure the ask which is likely a lot to recoup trading Sergachev, but the Avs shouldn't offer too much.
LW already has Landy, Kerfoot, Ghetto, Bourque and Neito, with prospects Kamenev, Bowers, Shvyrev & Greer that could replace at least 2 players on the NHL roster and with 2-1sts in 2019, another forward is likely to be added.
Doubtful if Drouin even plays with Mack by replacing Landy, but would be a an excellent 2-line pairing with Jost.