Linden vetoing Benning on the Pettersson isn't a narrative, it's what happened.
The GM should not be making the decision whom to draft. He should be involved in the process, but he should not overrule the scouts when they have seen more games. If you can't trust your DOS to make the correct decisions then fire him.
Promoting Brackett was a good decision. No one would argue that. Limiting Brackett's role, and letting him leave was not.
Again, where is the exact quote from Linden that he vetoed Benning? Even in the most recent draft (without Linden here) Benning ended up following his scouts' recommendations. Linden stepping in and giving his opinion or even order as to who to draft is not the same as "vetoing". People forget that Linden was Benning's boss and has a voice (final voice if he wants to) in the room. I can use your argument and say that if he didn't trust his GM to make the correct decision he should fire him rather than fight for his extension.
Also, the Director of Amateur Scouting doesn't make decisions on who to draft. He's more of a facilitator. Otherwise the same discussions come up. If say Bracket had a different opinion than most of the scouts then what? Is Brackett allowed to "overrule" his scouts?
It's a misnomer to use terms like "veto" and "overrule." If I'm the President of Hockey Operations and have final say then I don't need to overrule or veto anybody. Everyone below me should present their views and I make the decisions. Similarly, if I was the GM, I don't need to overrule or veto my scouting staff. They are suppose to do their jobs and give me their list but they are suggestions or proposals.
A lot of people here simply don't realize how different a team's NHL draft list can differ from all those "draft rankings" that are available online. They also don't realize that scouts can have different opinions about a player and still come to a "consensus" on who should be higher on the list. The reason is that at the end of the day the draft list needs to be put together. It's a group project with a deadline to submit your paper. Say a scout likes Bouchard over Hughes because he thinks Bouchard is a sure fire top 4 Dman while Hughes may not be able to defend at the NHL level. At the same time, say this scout agrees that Hughes has the highest upside. At the end of the day, the scout that preferred Bouchard may be on board with having Hughes higher on the list. A "consensus" would then be declared because that scout who preferred Bouchard was fine with ranking Hughes ahead.
Despite what some posters here would tell you, "groupings" exist and is incredibly relevant. If 10 out of 10 scouts preferred Glass over Petey based on size alone and so the preference was based on the slimmest of margins and none of the 10 scouts have a problem with Petey over Glass, is the "consensus" ranking really relevant if you're the GM and think the two players' size difference doesn't matter? Some posters here would like to convince you that there is a consensus and that's all that matters but as you can see it's pretty stupid as the preference can be based on certain traits that you don't consider that relevant.
Credit to the Canucks' scouting staff and Benning in 2017. They were absolutely bang on with that first round selection. Even Makar (had he been available) would have been an excellent pick.