Dota 2 will support some form of cross-region play and Valve is also "expanding the Steam infrastructure around the world so the matchmaking service for DotA 2 is able to provide the lowest possible ping wherever you are playing. There will also be some uniquely located servers that are optimized regionally for handling longer distance matches."
Players will be able to reconnect to games in cases of accidental disconnects, but will also be able to join games in progress to replace quitting players. "Players that want to improve their reputation in the game and community will also be able to help out by joining ongoing games that are missing players," explains Valve.
Players will still be able to control the heroes of dropped players or even have an AI takeover control for the remainder of the match. On the AI front, there will be bots available for offline games as well as co-op versus AI games with friends. "Weâ€™ll also have some specially crafted challenge scenarios, similar to things like Pudge Wars, which Iâ€™ll elaborate on in the future."
Spectating and replays will a lot of new features in Dota 2. Unless a game is set to private, you should be able to jump right in and watch a live game. "You can join a game your friend is in, see what your favorite clan is doing, or simply pick a skill level and a hero you like and it will find you one to watch." Replays will feature all types of data, graphs, and support fast-forwarding and rewinding.
There will also likely be a beta test at some point for Dota 2. Many more details about Dota 2 can be found at the first Q&A. Dota 2 is planned for a PC and Mac release in 2011.