Reasons why Finney could be Satoshi Nakamoto:
- He was the first Bitcoin recipient.
- He was working on an electronic cash system before bitcoin, called RPOW in which he used proof-of-work, but as far as I read did not solve the double-spend problem. He created the first reusable proof of work. (Hal really worked on proof of work)
- He lived in the same town where Dorian Nakamoto lived which can't be a coincidence. He either is Satoshi or someone got an eye on him.
- There is no satoshi activity after Finney passed away. (I know, not that good argument)
I think those are really reasons why Finney isn't satoshi.
If Satoshi decided to keep himself anonymous, why the hell would he make the first public transaction to himself, exposing his ID?
Additionally, as Finney was already working in a electronic cash system makes him the perfect recipient to receive the first bitcoin. Very few people would have access to bitcoin in 2009 (because no one never heard of it), and he had the access to that information.