They have the same 11th level ability (Rapid Attack replacing Armour Training 3) and the only other conflict is replacing Armour Training 4 at level 15.
Would it be reasonable to choose Lightning Strike over Fleet Footed and create a Mobile Dawnflower Dervish?
It seems like a neat combination and would match up well with light armour (or Web Of Steel from The Genuis Guide to Feats of Battle) for a nimble fighter, dancing across the battlefield.