Hello,
I stopped swaddling ds when he started escaping it and, like you, worried that the blanket would end up over his face. Does he seem to be escaping from it b/c it's annoying him, and he's trying to get himself comfortable? If so, it might be time to think about gradually withdrawing it.
This is how we did it -
We first started with one arm out of the swaddle (for the 1st day I had to hold his arm still as he fell asleep), kept it like that for a few days, then wrapped him with both arms out (but legs still wrapped) for a few days, and then transferred to the grobag. In black & white that sounds so easy, but it wasn't - it took quite a big of getting used to! But it did work eventually, so hang in there! I did have to stay in there with him for the times when his arms really did start flailing about, but he did eventually get used to it.
I don't know how you are doing it, but I believe the Aussie swaddle is really good if you haven't tried it (
http://www.babywhisperer.com/forum/swaddling-technique-aka-quotaussie-swaddle-quot-vt1439.html) - it takes a couple of days to get used to, but is very good.
I think the best advice to give is to try it. If your instinct is that it's time to give up the swaddle, try it, and see if that helps. If not, you can always go back to it.
HTH xx