Opting for Reirden over Trotz wasnt great. Oshie and Backstrom contracts dont look great either. And Mantha sucks
Reirden, from all reports, was the heir apparent not just from GMBM but from Ted himself so not much he can do there. There would have been riots in the streets if he let Oshie and Backstrom walk, and at least Backstrom is a guy that Ted would never allow to walk away. Mantha was a trade essentially forced upon him because Lavi refused to play Vrana.
The + on the Vrana trade was becuase of his poor Panik signing, but that signing was also universally praised when it happened. The biggest complaint that you can probably have with GMBM is him sending off ascending prospects for old veterans, but if your coach refuses to use them and you're trying to be competitive you do what you gotta do. About the only one I really think I can outright blame him for is Siegenthaler, and even then no one was turning down Chara at minimum. It's not his fault the team didn't want to give the 900 year old any rest days.
I think far to many people are caught up in GMBM being the "GM" because conventional teams have a very strict Coach answers to GM who asnwers to Ownership setup. Here, Ted was heavily involved in picking Lavi. GMBM is probably closer to a glorified Player Ops guy. This team is run exactly how and by who Ted and Co. want it to be run by.