Living in Akron Ohio (home of Good Year, Firestone, Goodrich, and several others at one time) I worked for Goodrich for 16 years. I still have many friends who work or worked in the tire industry in various capacities.
One of my oldest friends use to carve tire molds for Good Year, and he use to tell me about how many different designs they would do, and the company would test, before they found just the right combination of characteristics to make the tire perform just the way they wanted it to.
I would be very leery of changing anything about the tread design of any tire I planned on driving on the street with, other than having it "trued".
Probably the biggest problem you would encounter would be making it louder (as Kit Fox pointed out) but why take a chance of changing anything about a tires design that engineers have spent so much time perfecting.
Other than your brakes, I can't think of anything else more important on your car than your tires when it comes to keeping you from having an accident.