I've always put Pilates into the Yoga/Feldenkrais/Hellerwork camp. Excellent for flexibility, core strength and muscle tone. However where is the cardiovascular component? Also I have always stressed to only stretch as far as you comfortably can, sometimes I think people are encouraged to go past physical limits of their sedentary body and then have a musculoskeletal injury. Range of motion will develop, but it takes time, just as it took many years of inactivity to lose that flexibility.