We have not even gotten to Seattle and yet Valves policies post TI5 are already emerging.  Information regarding the first Dota Major Championship reveals that teams must have a stable roster if they want to be invited.  If a team wishes to be invited then they must have a stable roster from the 1st of September onwards.  Teams will also be allowed two stand-in player.

It was also revealed that Valve intend to play a more active role in roster changes in the future, and that a significant date will be December 4th, although it was not revealed why.

In recent years Valve have adopted a more passive attitude towards Dota, but now it looks like they want to play a more active role.  Stabilizing the rosters should have a positive effect on the game, as teams will have set times that they can change their rosters, it will stabilize teams as well as encouraging sponsorship, overall making the Dota 2 scene more professional.