Gamasutra just posted a rather longish essay of mine about Minecraft and what's wrong today with the intersection of games and intellectual property law. Here's the link. In some ways, I think I'm echoing Ted's criticisms of the new Star Wars MMORPG in the last post . In short: the more games become like movies, the less interesting they become. On the other hand, the more games let us express ourselves artistically and socially, the more interesting they become.
One significiant problem, as I see it, is that the current trajectory that intellectual property law is pursuing is much more supportive of the the former (games on rails) than it is of the latter (games that let players become authors).