Nice adjustments. One thing on the soupiness, I cut back the liquid overall for the gravy by 2 cups to accommodate for the Guinness. You would solve this problem by using the Guinness in place of the water in your gravy (that's where I substitute it to add the flavor).

As for adding new potatoes to the filling, since you have the potato topping, I think it's kind of overkill. If I were adding another ingredient, I'd put in zuchinni or squash.