I'm all for the morph effect. I do not think his ghost should be young Anakin, but I also think he should have some resemblence to Hayden. If it's a totally different person, it wouldn't be a good flow. I know everyone changes as they age, but Im sure if you had a picture of a young Sebastian Shaw for example, you would most likely be able to tell that it's the same person. So, unless Ady is going to change Anakin throughout the prequels (Pretty impossible), the morph is the best route IMO.