Yes, a long time ago I did a vegetarian version using that crumbled vegetarian protein, but most of the time if I leave out any meat or poultry (or even want to bump the umami in the turkey version, I rely on well-sauteed chopped mushrooms for the meaty flavor and the gravy. This time I only used the white button mushrooms, but often I'll use cremini and a mix of wild mushrooms. Plus, I have a jar of pulverized dried porcini in my spice rack and add that to a lot of braises. In this version I added carrots, celery, zucchini (small cubes, they kind of got lost in there), a bag of mixed frozen vegetables (peas, green beans, corn) plus a lot of onions which I started sauteeing with the mushrooms. Lately when I cook a dish with ground turkey or ground chicken, I don't brown it in a dry pan, since it's got almost no fat and it gets rubbery if cooked too long. I try to poach it in the thickened liquid, in this case after I'd sauteed a lot of the vegetables, I put the sauteed mushrooms and onions (held separately) back in the pan with the liquid they'd released, added a few tablespoons of flour, and some chicken stock, and then gently cooked the turkey in that little bath. After it's no longer pink I add the remaining cooked vegetables back in.
I was a little disappointed that my whipped potatoes kind of deflated while baking. I think maybe I was trying to stretch too few potatoes and made it a little insubstantial. Still tastes good, though I'd spiced it up a bit but in the end the spice didn't come through as much as I'd thought, so a dash of hot sauce helps!