Not sure what you think deadline additions last year have to do with anything.
The first decision he made was to not re-sign most of them. The second decision he made was to instead overpay worse options that didn't fit together.
You keep talking about the first decision, when everybody else is talking about the second decision and the better paths he could have taken there.
There's nothing about them that makes them more "character" players. In fact, the "character" of some of those players has been historically questioned.
A big part of the reason that the Leafs ranked low in offense from the defense is because we prioritize higher quality shots when possible. We try to get pucks in close around the goal and create movement there, instead of blasting pucks from the point. Even when we get shots from defense, it's often going for tips. But our offense overall was fine, so this tends to get wildly exaggerated as an issue.
Is it an area that could be addressed if Treliving wanted? Sure. But the solution was not to take out a defensive defenseman and big PKer that has historically taken a lot of our heavy matchups, and fill his spot with a broken down has been that has to be heavily sheltered because he's been one of the worst players in the league defensively for years.