Bitcoin should be forked and Satoshi's 1 million Bitcoin destroyed completely, if he really owns that much.
A sudden withdrawal of of 1 million (or large gradual withdrawals) should be regarded as an attack on Bitcoin.
Or it should be frozen for now until developers are sure no one is going to withdraw the whole thing and crash the market.
This person or a group of people gave us something we all value, and this is how you want to express gratitude? By destroying the money or taking it away? And for what, only out of fear that once this money might be withdrawn and make the market bleed? How many whales would panic if such a fork went through? First Satoshi's money, their fund can be the next to go, right? Not to mention the FUD such an event can generate. Some say you can fork whatever you want, just don't expect others to join you. I, however, think that a person who cares about Bitcoin and the market would not go for an idea that can split the community into two once again, making it weaker.