From Gosugamer

A few weeks after the huge disappointment from the community at the lack of a Halloween event, Valve finally responds to the community and announces a new and improved Diretide that will hit the client very soon.

With the hype of a special event reaching a fever pitch near Halloween, the community was justly disappointed at an apparent lack of Diretide. The absense of any Valve response only intensified the communitiy's rage. Having vandalised numerous tweets, Facebook updates, Metacritic reviews and even Cyborgmatt's phone number, the community has somewhat eased its anger in the past few days. (See here for Gosugamers's view on the community's reaction).
However, for the few who harbour hope that Diretide is still coming this year, Valve finally sheds their own opinion on the issue in a blog post. They revealed that a huge patch, along with Diretide, is in the works and will be implemented in the near future with Diretide relaunching in the next update. In addition, Valve stated that the next Diretide is " more fun than before". The quote below is taken from the source blog post;

"Due to our poor prediction of your reaction, and the team being focused on the next update, we didn’t spend enough time thinking about talking to you about our decision. As a result, by the time we’d realized we’d made a bad decision, the pitchforks were out."

On another note, Metacritic reviews are improving by the minute ever since the blog post.
Source:Dota 2 Blog