I'm in a similar situation to your wife. My hemoglobin also dropped to a 7 as a result of my endometriosis and frequent, severe periods. I can no longer take NSAIDs and have to use narcotics and/or visit the hospital for pain management. I'm surprised they are still letting her use the NSAIDs as that can signifigantly increase the likelihood of anemia.
I am also looking at a hysterectomy. From what I understand, it is not a cure; however, if her most severe problem is anemia it can really help with that because she won't have monthly periods anymore. In my case, becaues the endometriosis (at least at the time of the last lap) was confined mostly to the uterus and the bladder, I can keep my ovaries which means I don't have to go on HRT either. Unfortunately, the endo can (and often will) keep growing; however, it can be a good fix for anemia and in some cases pain. Whether or not it helps her pain depends largely on the cause of the pain. For me, I generally only get pain during my periods and it's mostly from uterine contractions and the expulsion of large clots, so I'm optimistic it will help with the pain as well.
I have done a lot of research, I'm only 27 and I don't have children or a spouse so the doctors are taking the decision very carefully, if you want you or your wife is welcome to contact me and I can tell you everything I have found out so far.