DS is still swaddled. We tried him without it around 5 months, and it seemed ok for a couple of weeks but then he started waking every hour and it was back to swaddling! He's in a sleeping bag now, and we use muslin wraps. He gets one arm out and sleeps like that. Weirdly, he doesn't sleep well if he has both arms tucked in, and if we unswaddle him he wakes up in a few seconds. If he moves his arms he gets out of the swaddle completely, so the swaddle is really just a gesture, but he likes it. When he wakes up he rolls and the swaddle comes undone, so that doesn't bother me. When he starts to want both hands out we'll ditch the swaddle.

Your DS would tell you if he flipped over and got stuck, but maybe you could not swaddle him very tightly (if you decide to ditch the woombie) so he can move his arms if he rolls?