High Dynamic Range lighting with eye adaptation and bright pass is implemented in the Glow engine. Plus gamma-correct rendering. Color Transformations (hue, saturation, brightness etc) were started. Color transformations can significantly improve quality and mood of 3d rendering. Just remember cold tones of Matrix movie or color shifts in Left4Dead.
Also scalability of task manager was improved by moving task execution into Intel Threading Building Blocks - cross platform optimized library for multi core programming (same is used by Unreal engine and numerous game studious)
The scene graph became multi threaded, resource manager was improved by smart_ptr + weak_ptr scheme - better memory leak tracking, reference counting for resources, plus resource manager became concurrently multi threaded - it allows read-write access from different threads (jobs).
