If he was satoshi he would just sign a message with the genesis block's private key saying so. He wouldn't announce that he's going to move an early coin on the bbc. It's simultaneously the most convincing proof and the easiest proof to do.
I agree. It's very hard for me to believe that he can both have been so clearly well-versed in crypto and with its beauty, enough to create a masterpiece like bitcoin, and at the same time hesitate to just sign a message. Not only is signing something convincing and easy, it's taking advantage of that same beauty of crypto that he should appreciate so much.
It seems backwards to me that someone like Satoshi who obviously does value privacy and anonymity would get on BBC and declare "I am Satoshi, and I want to be left alone" and yet at the same time not take the cleanest, least extravagant option of just signing something.
In my eyes, he's a fraud until he does it.