I think the thing with Sucker Punch for me is that the film, itself, doesn't make any statements. It doesn't go out of it's way to present any kind of message, it just sort of happens, which I guess is where the style over substance criticisms come from.
The core plot, in itself, is admittedly little more than a framing device for some phenomenal set-pieces, but what has kept it in my mind is I guess the whole ambiguity of the thing.
I suppose the trouble here is that, as the film itself is pretty devoid of an overt message, it falls to the audience to determine whether there are subtle messages contained within or if it's just a mindless popcorn flick. Personally, the thing that resonated more with me is the whole fact that the film has taken what appears to be it's primary selling point - hot girls running around in revealing outfits blowing shit up - and used that as a vicious attack on those who are going to see that in action. There's one - count 'em - one male character in the entire film who doesn't objectify the girls in some way, so in objectifying the girls as a viewer you're no better than the creeps in the movie.
That's the biggest message for me. I've never left a movie feeling slightly guilty in this fashion before. There's much more to analyse, particularly in terms of I guess determining whether some things are plot-holes or intentionally open avenues to debate and derive meaning from, but I felt the message on objectification was pretty striking throughout.
Looking on Wikipedia it appears a lot of things had to be cut so it'll be interesting to see if any 'Director's Cut' adds anything particular to the experience.