Goal #1: Reunification through Common Understanding
As part of the design process, the R&D team must boil down the RPG into its most basic component parts. Using those rules elements, the team must then build an easy to understand game system that incorporates the most iconic elements of D&D in prominent roles. Anyone who has ever played any version of D&D must recognize and understand its most important elements.
Goal #2: Reunification through Diversity
Traditionally, D&D editions have focused on specific play styles. This approach has fragmented the community over time. The next iteration must stretch the system to cover a wider variety of play styles through character and DM options. By looking at past editions and incorporating their elements as core or optional rules, we can allow players and groups to place the focus where they want it.
Goal #3: Reunification through Accessibility
D&D has traditionally required large amounts of time, a large play group, and a sustained commitment. The design process must focus on play time, group size, speed of play, and length of campaigns, with an eye toward reducing the minimum required from each area. Players who want a longer play time and so forth can easily scale up the game to meet their needs and opt into the various rules modules we'll provide or that they'll build themselves. However, our standard goal is to remove minimum group sizes, allow for a complete adventure in one hour of play, and satisfying campaigns in 50 hours of play.
Game Design
The new system must create a mechanical and mathematical framework that the play experience of all editions of D&D can rest within. One player can create a 4th-Edition style character while another can build a 1st-Edition one. Complexity and individual experiences rest in the players' hands. That experience is more important than the specifics of the math. In other words, if the math works but the game doesn't feel like D&D, we've failed. If the system is sound, but it can't replicate D&D's classic adventures or seamlessly support any of D&D's settings, it isn't the right system for D&D.
More importantly, we must look beyond the mechanics of the game to focus on the archetypes, literary tropes, and cultural elements that built D&D. We must build a fighter that resonates as a warrior, not one simply cobbled together with mechanics pilfered from D&D's past. The key game experience of D&D lies at the game table. Our work must start by focusing on the key elements of D&D and the unique traits of a tabletop RPG. The mechanics must support those two factors, not the other way around.