In an earlier SceneJS there was an an option to suppress geometry visibility while textures load, so it looks like it would be useful to have that back.
You mean the waitForLoad flag? I noticed this flag and checked it out.
In v2.0 source code You have it already implemented (but just as a
property without any effects), but even without this flag the faces
should display the proper parent material/texturee values until the
own texture is loaded.