Put oven racks in upper and lower thirds of oven. Line 2 large shallow baking pans (17 by 11 inches) with foil. Put pans in oven and preheat oven to 500°F
Pat wings dry, then toss with oil, salt, and pepper in a large bowl and divide between preheated pans, spreading wings in 1 layer. Roast, without turning, until golden and tender, about 35 minutes.
While wings roast, simmer vinegar, soy sauce, and sugar in a 1- to 1 1/2-quart heavy saucepan, stirring occasionally, until reduced to about 1/3 cup, 12 to 14 minutes. Remove from heat and stir in butter until melted.
Remove roasted wings from oven and let stand in pans 1 minute (to make wings easier to remove from foil), then transfer with tongs to a clean large bowl.
Pour balsamic mixture over wings and toss to coat well. Let stand 5 minutes, then toss again.