It's an interesting interpretation. I'm not sure it's in any way invalid, but I do have some problems with it.
Well, any story in which characters are in some sense entirely not characters performing actions but symbolic representations of philosophies or... I dunno, Jungian archetypes?... whose activities serve only to reflect upon those philosophies/archetypes and their successes/failings is going to have a hard row to hoe. Not least because those "characters'" successes or failures is going to starkly be due to the whim of the storyteller. If the failure of Babydoll's plan is the failure of third-wave sexualized feminism, if I disagree with the notion that third-wave sexualized feminism has failed in the way portrayed, the whole thing kind of unravels, even having come so far as to recognize all the symbolism the director intended.
When I saw "Sucker Punch", I was most irritated by the notion that Sweet Pea was the "actual hero", and I guess I still feel that way. I felt that the earlier story of Sweet Pea coming to the asylum to protect her sister Rocket might be a story in which she was a hero, but the one we were seeing was one where Babydoll was the instigator of all the action; that being the case, saying that Sweet Pea was the hero was simply not a choice the movie had the right to make for its audience.
Yes, in many ways Baby Doll's plan was a failure. But it wasn't a failure because of Baby Doll, aside perhaps from her excessive willingness to put the others at risk, a risk each girl agreed to take on; it was a failure because of bad luck, and one girl's reaction to setback being an unfortunate decision to confess the plan. And while Sweet Pea's desire to keep Rocket safe might be admirable, what does she offer in opposition to Babydoll's plan, other than a continuation of the status quo (which appears to consist of the girls continuing to suffer routine sexually abuse until their captors tire of them and decide to get rid of them?) What's "heroic" about that in this story?
In the final hour, it's still Babydoll who has to rescue Sweet Pea and choose to sacrifice herself.
Sucker Punch was certainly an interesting film, and not one I'm sorry I saw, but however one chooses to interpret it (and even to the extent that many interpretations run into their own road blocks), I think my ultimate description would probably have to be something like "ambitious failure".