Hey, sorry, I’ve been away from the internet for a few days!
Just to clarify, you have models importing as separate meshes now, which is great. What you are wanting is to be able to assign specific materials to arbitrary surfaces, essentially allowing you to texture a model that is untextured in sketchup?
If this is what you’re after, I’m not sure that adding an SKP import option would even help you, as it will still have to translate to UE4s mesh format which works on set material assignments for groups of mesh faces (usually referred to as mesh batches). You can see these elements in the static mesh editor when opening an imported FBX, and these are editable per instance when placed in a world.
If you want a finer grained control than this, I would go for a layered material approach.
Finally, you seem to ask to be able to edit the imported meshes themselves in UE4 - if you mean editing the actual mesh geometry, this is not currently possible, though we are currently discussing the future of the geometry editing tools in UE4 and this might be a direction we take.
I’ve opened a dialogue internally about sketch up - I’ll let you know where it goes!