- The Multiclassing focus of the system. I would change the way classes worked, but the general idea of mixing and matching abilities of different classes or roles is sound. It avoids the complexities and imbalances of a fully fledged point buy build system, but still gives a lot of ways to tailor your character and create interesting archetypes (including unusual ones). For example, mix Strong with Smart!
In D&D classes represent tactical roles regarding the adventuring day (old school) or fighting monsters in the "encounter-arena" (modern 4e). How would you envision classes for the modern D20 game and why?