Irawan, I think that doing lots of rough sketches first to get out usual 'cliches' may eventually bring you to a 're-imagine' that you can be satisfied with.
I personally like the sketch for Repunzal, and can understand some peoples posts about it not being too re-imagined. I think maybe you could elaborate the hair more; step away from your usual comfort zone, and push the story more.
Repunzals hair could be a forest; or she could be a sky princess and her hair is the clouds; or a kind of sea creature with long tentacles.
We have plenty of time to flesh out something original. Take the elements of the characters, and change them dramatically. The story will always the same - just add that twist to make it different from the usual fairy story...