I've just printed my first roll of Ilford HP5+ from my M645 Pro, shot entirely with the standard 80mm f/2.8 N. Was blown away by the negatives. I've developed a reasonable number of 35mm black and white rolls, but the detail and tonality of merely the *negatives* was mindblowing. I think the larger negative size and the higher resolution and tonality that you get gives you more room for creative experimentation - and boy does it reward you when you get things right.
No more squinting at piddly little 35mm frames.
But in cases where you need to shoot off multiple frames in the hope of capturing that elusive moment, etc, or where every gram of weight counts, that's where 35mm fits I guess.