You don't neccessarily need a back ground, just a different color shirt to put it on. If you do the things you said, add more details then it should work.
I think the light blue would give it a natural sky-like background. I agree that the outlining is way too heavy - I liked the look of it in v1. Also, I'm not sure if I understand the dirt underneath. Are those ants?
It might be that just more flowers extending out on each side is the way to go - not necessarily bigger ones.
I love the petals all over the place. Very pretty.
Anywho, Still going to add some light blue highlights on the dress and flowers and probably try and fiddle with the outlines, they still are bothering me a bit
it's the shoulders that make it kinda ambiguous. women usually have sloped shoulders. it kinda looks like she's shrugging. have you thought about maybe making her arms thrust out, like she's spinning amongst the flower petals? because that's what the background kinda makes me feel like. her pose is a little too static.
The over all theme is sorta static and sad, so her blank stance works as is, thought I was think of having her hands open and her arms out a little more to make it seem like she's interacting with the petals
She's pretty and not going anywhere like the flowers
Fiddling with it more later