I made Hamelman's Workday 100% whole wheat at 85% hydration with 15% walnuts. Photos at https://photos.app.goo.gl/M8LXr8Pe6rF11uZR9 (double loaf; link to the formula in the photo captions).
What's unusual is that after fermenting the levain, I ran into a time constraint and put the levain into the fridge, for an unplanned extra 24 hrs of retarded fermentation. When I finished the loaf it had distinctly more flavor than usual, and might even have had a slightly more open crumb than usual. I was happy that it just survived the extra time in the fridge, but the results were better than usual.
In particular, I'm surprised that the extra time just for the levain had such a big effect. BTW I use a 100% dark rye starter; rye doughs don't usually do well in the fridge.
Louis- I think you should intentionally put your levain in the refrig for a day the next time you make this bread to see if this really did contribute to your better outcome. Then, of course, you could bake the loaf the usual way again to have another comparison. You continue to make really nice loaves with 100% whole grain. You have probably shared this before, but what is your usual timetable with this bread? How long a bulk fermentation do you usually do at what temperature, for instance.