I have done a good deal of experimenting with milk in pizza crusts. I have noticed a huge impact on dough flavor, in a positive way. It, however, is not a traditional flavor that I associate with pizza crust (being someone brought up on mostly NY style pizza). It also has a huge impact on crispness. This can be a blessing or a curse, depending on your oven temp, and there are times that I find it will make a pizza too crispy... while in other situations that extra crispness is exactly what I want. Dough texture is softer, almost in the same way bromated flour makes a dough lighter and more tender after cooling (I know that its technically strengthening gluten, but thats what bromate does for me). The negative of milk, is that it will bring lots of extra browning to the table, so you have to be careful of oven temps when using it. At one time, I was using a very small amount of dry milk for pizzas with a 700-750 ish degree floor. Surprising, after my previous comment. As long as the pies were closely watched so that the bottom didn't burn, I was getting major compliments on dough texture and flavor. It definitely added crispness to what could easily end up being a floppy pizza (created by the lack of convection/drying in my electric oven). In my opinion there would be no need to use milk in a WFO because the crisp is already there. Surprisingly, I did not like what milk did when making pizza at the more traditional temps/styles that you see it being used (500 or so). This is just a personal judgement, though. Something was just off with what it did to the texture for me.. Of course, that could be exactly what someone else is looking for.