Fox at MMO Sanctuary sent a few questions Executive Producer Shannon Posniewski's way. You can read the interview here.
From the article:
We're planning on two things: Adventure Packs and content refreshes. Adventure Packs are great big story arcs, with multiple missions, locations and bosses. Any hero level 11 and above can go on the adventure. Adventure Packs will scale to the team's level and size, so everyone can experience it. Players can also replay these adventures.
We also plan to revisit the content for some levels and add in more to provide a bit more variety. We're currently considering doing something for the 20-30 range, though these plans aren't final.