This year's Dota 2 The International 10 (TI10), typically held in August, is still a ways off but Valve is already planning for next year's DPC season by introducing a regional league system for competitive Dota 2.
A new league will exist for each major region in the Dota 2 scene: China, Europe, North America, South America, Russia/CIS, and Southeast Asia. Each regional league is split into 2 tiers, with relegation between tiers occurring at the end of each season. Relegation allows the possibility for new teams to enter the league through the second tier, and possibly make their way to the first tier.
The year will be divided into 3 seasons, with each culminating in a major tournament. Invitations to majors are determined by a team's standing from 6 weeks of regular season play. Prize money and DPC points awarded for the majors are fixed. The top teams, by DPC points, at the end of the 3rd season will be invited to The Internationl 11.
Valve gave this as their main reason for implementing the new system:
We believe the consistency and regularity of the league throughout the year, paired with a flat and deep prize pool distribution will, over time, nurture healthy and strong Tier 2/3 competition.I hope that this change will be healthy for the Dota 2 scene. It seems to promotes stability in rosters which could lead to stronger teams overall. Dota 2 is, in my opinion, the best esports title that's fully and natively playable on Linux, and I would like to see it have continued success.
For the full details on the upcoming regional league changes, check out Valve's official blog post.