Also to add, in no way am I saying Marner is poor defensively, just that I give the SLIGHT edge to Boeser.
by the measurables, Marner was a considerably better defensive player this year. Much better Corsi/Fenwick, much better relatives of both, much better giveaway to takeaway ratio. Imo, it was also really evident to watch, Marner was incredible at stealing pucks back this year - regularly caught defensemen along the boards and came away with the puck and was very good at picking passes in the neutral zone
I think it also gets lost that Marner was expected to be a really good defensive player like Giroux, people fixate on his offense and that's he's small so they expect him to be a Drouin type