Or... He would hate the fact that people are speculating and hoping to get rich, so he'd dump thousands of coins from his stash of almost a million.

As with everything else when it comes to Bitcoin, it could be either of two radically different things.

Well one can speculate eternally, but one thing is certain: this is the man (or group) that has developed a very complex client without almost any support from the outside, and was there keeping it going for almost two years before any real amounts of users really adopted it, and before it was clear to anyone that this thing could really shoot. Imagine spending that much time and not not knowing for two years if it was a waste of time or one of the biggest contributions to the internet community/humanity ever