In some parts I agree that a lot of motion has been lost, on the other hand I love the detailing. Iīd definitely leave the belly alone, the curves look good as they are.
If you really want to go back to the feel of the original sketch I think you need to rotate the outstretched leg again to get that dynamic feel back into it. Right now the problem is that the pose of the arms suggests motion, while the legs indicate that sheīs sitting. The other possibility would be to redo the arms (and possibly the hair) and change them to a more relaxed state (such as placing both hands with straight arms on the imagined surface between her legs).
All in all Iīd probably leave it alone. It looks great, and overdoctoring it now probably wonīt help all that much.

@sharprm: I donīt think your edit works, there isnīt much movement to it since to make it into a proper "landing" pose youīd need to rework more than just the rear leg. In any case, I donīt even think that leg is the issue. Also: wtf about those leaves???