Adaptive subdivision for displaced meshes was greatly improved, yesterday.
That is really cool to obtain one unique surface instead of overlapping, crossing or floating exploded parts of mesh.
There is no more gap on boundaries of materials.
But the result is really counter-intuitive according to chosen shading type.
Currently, subdivision surface modifier has to be the last modifier to exploit adaptive subdivision.
If we try to add a weighted normal modifier after it, we are loosing displacement.
We have to use same material or a coherent displacement texture through all materials of meshes to obtain a pretty result.
If we could have a tweaking of normals applicable after subdivision or a respect of sharp edges by adaptive subdivision ; people could obtain good results with multiple materials without having to deal with creation of a complicated texture.