Nope. I have a first edition, and noted the minor changes to the setup for the Ishida forces on the board and on the blocks. That is the only change that I'm aware of. Doesn't seem like a reason to buy the game again.
What would be a good reason to buy the new edition would be to give it (or your 1st edition) to a friend so that more people play this fantastic game.
... so a potential worthy opponent can get the practice solo gameplay necessary to become worthy!