You're in good company here! We're a knowledgeable bunch because draw off our own experiences the experiences that we read about on this forum.Specifically I took a suggestion from this board to my nuerosurgeon which led to a procedure that ameliorated my problem.
In reference to your daughter, I can only draw on my own experience and from general (unofficial) consensus of other's experiences that they've shared on this board.
First thing I can address is the amount of time it's taking her to recover. There are many factors that go into a recovery time and it sounds like your daughter had a lot of those factors. For instance, the fact that (it sounds like) it takes a while for her malfunctions to be pinpointed. It's the curse of the slit ventricles, (i've got them too). The problem that it poses for recovery is that the longer your daughter was living with a shunt malfunction (headache, dizziness, blurry vision, balance issues)the longer it takes for all of those things to return to baseline. For example, I had sunset eyes and blurry vision for two days before a shunt surgery, and it took two months for my vision to return to normal. It was incredibly frustrating, and I only had that symptom for 2 days before it was corrected!
Another thing you mentioned was that it sounds like she had incisions in her abdomen and head, indicating that they replaced the entire tube. This is in fact a pretty major surgery and recovery should be assessed separately from the short surgeries on the proximal catheter at the end. When new tubing is put in your body many times there is bruising along every spot that they had to jam the tubing through (sorry to be crude but that it literally how they have to move it around in the body sometimes). The small incisions that you see on the outside of your daughter's body, are no indication of what her body went through, and that's one of the hardest things to remember. Kind of like, "I look fine, so why do I still feel like crap?" Because you just had major surgery and your body needs compassion and understanding. Also, if I recall she had extreme change in pressure from her overdraining shunt to a normal pressure, normal working shunt. The head needs time to readjust and recalibrate.
As for the pain she's still having, again, remember that she went through MAJOR surgery, and every single movement that a surgeon makes on our bodies while we're sleeping, can cause pain that last far past the extent the surgery. I think also that the pains could be due to any variation in a surgeons style. For instance, my incision site is at the front of my head and the incision was always curled to the back. Well in December the NS decided to curl the incision towards the front just almost reaching my hairline. Because of this my scalp and incision was EXTREMELY sensitive (and still is). The nurses told they thought it was because we have so many more nerves in our faces so the fact that the incision was so close to my face probably lit up a bunch more nerves.
You seem to be a very caring and concerned parent. Give your daughter patience and compassion and teach her to be patient and compassionate with herself. Every recovery is different. I know when I was a kid I had many revisions and so many times i'd be out of the hospital the next day and back at school the next. But as I've gotten older (i'm 27) it has taken me a lot longer to "bounce back" after surgeries. I've had to be patient with myself and have compassion with my body and not expect so much of it all the time. I hope any of this was helpful or hopeful.