There is an interesting discussion ongoing regarding to Waylands current memory allocation model and how this could be scoped better to be more suitable for different graphics architectures.
The rendering model with Wayland is simple and therefor powerful. The key part is the possibility to share a video memory buffer between the client and compositor. This all is currently done through DRM which also makes DRM an essential part of the whole Wayland concept.
So what has now been under the discussion in the Wayland forum is how the current model could,
a) provide interoperability between client and server. Different Wayland clients could more easily discuss with different Wayland Server solutions
b) isolate the important memory handling part away from the core protocol. Allowing Wayland to be used more easily with other memory architectures.
The proposal is to split the DRM specific part to an separate file which would solve both of these problems and would once again put Wayland closer to take the place as the future Linux graphics solution.