My daughter is 10 1/2 mos now and we had the same issue at 4 mos old. She was breaking out of the miracle blanket and beginning to roll over. I emailed the miracle blanket for advice on stopping swaddling. They said I should definitely stop using the miracle blanket. They recommend using it until 14-16 weeks or something (I cannot remember exactly, but it states it on their website). They had two recommendations, cold turkey or the slow wean off. I went with the cold turkey which they prefered and stated would take less time. I do not remember the exact process they recommended with the slow wean, but I think it was one arm in and out thing. It was hard for about 2-3 nights and then she was sleeping through the night again.
Hope this helps. If you have specific questions, I do recommend emailing the miracle blanket people. They replied to my emails quickly and I remember finding them very helpful. I love that miracle blanket. I was sad when I packed it away.
Hope this helps. Good Luck!