A new update just hit Dota 2, and first things first: you do not, and will not, have to pay to unlock any hero in the newly confirmed to be free-to-play Dota 2. If you want, however, you can spend your real-world money in order to unlock neat aesthetic pieces for your favorite heroes. Is Nature's Prophet's beard not awesome enough for you? Get a new one! Is Kunkka not enough pirate for your liking? Now he can be! You can mix and match various pieces of equipment to make each character your own.
Battle Points and leveling up have also been added, and it looks like each time you level up you'll get a random item, similar to Team Fortress 2. Steam Workshop integration has also been added, so if you have the chops, you can design your very own items and they could be included in the game! I suppose it's only a matter of time now until trading is integrated, right?
Some Ogre Magi and bot AI fixes are the only real gameplay changes to note as there is no new hero added in this update. There are, however, three silhouettes on the bottom of the update page. The Internet tells me that they are Mortred, Chaos Knight, and Gyrocopter (!!!). Oh man, I can't wait to play Gyrocopter.
Official patch notes:
DOTA 2 BOTS