Better usage and system will impact results but it’s not going to make someone not good enough for the NHL spontaneously good enough.
The biggest factors in growing as a player are level of competition & ice time. Morrow has played 104 NHL games in 4 years & has played 3 AHL games since the 2014 season. He's been a healthy scratch for a 2/3'rds of his NHL career. It's pretty hard to improve on the bench.
Paul Postma found himself in the same position. Yes Postma is presently at best a 7/8 defensemen, but had he had the opportunity to play 240 NHL games over the past 3 season he'd almost certainly be a far better player at present.
There's a very small window of opportunity for players & the competition for these opportunities is substantial.
At this point it's doubtful Morrow ever become a fixture on any NHL blue line. There's a lot of factors as to why a player with his pedigree hasn't progressed, but I'd suggest if he wasn't ready for a full time spot on the Bruins blue line back in his 3rd pro season, he should have been left in the AHL until he was either ready or until waiver eligibility forced the Bruins to make him a healthy scratch.
In my opinion calling up any 21-24 year old player from the AHL only to have him watch over half a season from the press box is terrible asset management.
