Old post but I'm wondering...The picture I saw didn't show the actual construction done. Why is it assumed the mason extended the drain mat into the ground? I'm not a mason by trade but, couldn't the drain mat stop at the sill? If the sill plate is recessed off the foundation face by 3/4", that would allow you to compensate for sheathing and a drain mat right at the sill/stem wall/foundation transition. With proper flashing and weeps at that point, the mason could have floated a scratch coat over the transition and set stone all the way to grade with a thinset or mortar. No drainage would be needed on the stem wall behind the veneer. Properly done, I don't see how stone down to grade would be a problem. I wouldn't run a fake stone to grade for capillary effect but natural stone would be fine I think.