I would say, this is not because a team is at the bottom of the standings, than this is easier for a GM. I mean Ottawa and Buffalo? Im still waiting. At one point, a GM need to build something. Ottawa getting chychrun, sanderson, chabot? For me this is 3 same kind of defensemen. Why?
Buffalo have a lot of tiny forward, why?
Montreal started their rebuild way after theirs and I consider them very close.
And good GM knows when make trades, bet when the values is at the highest (or lowest). the timming, the bluffing part.
Also, I don’t think it’s because your team make playoff, that your team has a good GM. I hated Marc Bergevin even if we were making playoff. He was not able to build a team, he was keeping 1st round pick when Price was the best goalie in the league, he was litterally a passive GM. I could continue the list. Anyway, a good GM to me is a good poker face, he knows when to buy, when to sell etc.
Don Waddell was a good GM in carolina. Losing many players (faulk, hamilton, trochek, niedereitter, etc. And still being competitive. Good GM takes best choice possible even tough one.