Because I cannot take Lucas trying to make the prequels 'match up' with the OT.
It looks out of place, Luke just unmasked Shaw on the death star so it should be the same person he unmasked. If Lucas believed in his own logic, why isn't Qui Gonn there?
Hayden Christensen is terrible (IMO) in the first place, why must pop up in the OT?
It's just another excuse for Lucas to change for the sake of change.