From the FAQ, emphasis mine:
Why should I participate in the Dungeon Masters Guild?
...Your content can be rated and reviewed by fans who purchase your adventures, allowing you to improve as a designer, and allowing Wizards to easily identify the best creators for additional publication opportunities.
Mike Mearls also stated in his Reddit AMA when DM's Guild launched that identifying new talent was part of the intent of creating the guild. (ENWorld summary)
Last year (2015) Adventurer's League put out an open call for new designers; the article linked above contains tips on good AL design from the WotC staffer who reviewed all of the submissions. Highlights include:
- Proofread, and have someone else proofread;
- Know the rules;
- Avoid humor (it's really hard to communicate it well in static text);
- Leverage existing material.
Since you're already publishing, it may be that you can cut the line a bit. You might be able to float some of your material past WotC's AL staff--yes, it appears to just be one person--and see if you can get traction. But there're no guarantees in life.