I had a stoma for half a year, but I cannot tell for sure how good it can work, because I had a mild chemotherapy at the same time after my surgery for bowels cancer (at the same time my colon was removed and the pouch was built).
I heard from several people that a stoma can help to get rid of inflammation and meds when everything else fails. I was recommended it myself by doctors in hospital, as I have a chronic pouchitis for 17 years now. But I can keep it in check by occasional use of antibiotics quite well in the last 18 months (before I had antibiotics treatments only at hospital, when I was already completely exhausted).
A loop ileostomy has the advantage that it may be reversed to the pouch again if you don't feel better. And it can on the other hand be changed to an end ileostomy, which is easier to care of, if you want to keep it. But in the end it is another surgery and a harm to one's physical integrity, as you mentioned. So not an easy decision, I'm struggling myself.
I would also consider Scott's advice about biologics. I'm through most of the latest meds for UC / Crohn's, but none of them made a change for me.