Implement hardware acceleration (like OpenGL,Vulkan). (this seems to be some support already with the GLDraw)
Scene graph-like data structure for efficient UI management.
Use retained mode rendering to store and manage UI element states.
Support asynchronous loading of resources and UI elements.
Minimize unnecessary redraws with efficient invalidation and update mechanisms.
Develop a  animation and transition system.
Integrating widgets to use this styling,  override default behaviours