DOF is just not quite there. Some elements of the flower and butterfly need to be sharper. Also the background could do with being a bit further out of focus to really isolate the main subject.
The compsition is pleasing to me, but the very small depth of field makes most of it seem out of focus. I understand that that is hard to change using a telephoto lens, but a couple flowers and the full butterfly in sharp focus would have made this picture pop.