First (and most importantly, of course) this week's patch brings Rubick, the Grand Magus
His abilities are as follows:
Q - Telekinesis: Rubick uses his telekinetic powers to lift the enemy into the air briefly and then hurls them back at the ground. The unit lands on the ground with such force that it stuns nearby enemies.
W - Fade Bolt: Rubick creates a powerful stream of arcane energy that travels between enemy units, dealing damage and reducing their attack damage.
E - Null Field: Rubick's mastery of the arcane protects his allies against weaker magics, granting them magic resistance.
R - Spell Steal: Rubick studies the trace magical essence of one enemy hero, learning the secrets of the last spell the hero cast. Rubick can use this spell as his own for several minutes or until he dies.
That's right, he can steal spells.
Other than that, the major announcement in this patch is Valve's plan for Tournament viewing. Essentially, you'll be able to buy the ability to stream tournaments in client, with caster commentary and such, and Valve will split the proceeds with the tournament organizers. The Defense is the first tournament which will be utilizing this concept. It starts today and tickets to watch any of the matches (and download the replays) in-game is available in the Dota store for $5 USD.
If you'd rather watch for free, they'll be streaming normally on JoinDota.