I feel like they've really mismanaged Robertson. This team has been so desperate for secondary scoring, that they've just been yo-yoing this young prospect up and down to the Leafs/Marlies for years.
Go look at how we developed Brown, Johnsson, Moore, Engvall, Hyman, etc (i.e. guys that we successfully developed). These guys weren't given a taste of NHL action until they had ~100+, and in some cases ~150-200+ games against men, whether that was in the AHL, SHL, NCAA, etc. They weren't brought up until they were ~23+ years old.
Robertson though? He's only 21 years old right now (i.e. younger than when any of those guys got their first taste of NHL action), and he's already been brought up to the NHL in each of the past 3 seasons. He should have zero NHL games under his belt right now. He's not ready today, and certainly wasn't ready when they rushed him into the lineup as a 19 year old. He should be focused on developing his game in the AHL right now.