IMO layers could complicate the whole thing, they have an analogue in two-d work but for three-d its a forced analogy. In pro/e and sketchUP layers are a real mess. They end up interfering with groups or assemblies unless you are super rigorous in their use (rigorous is not the word I like to think of with using MoI).

In my work flow I export groups to new .3dm and .skp files each time I have something I think I'd like to capture. The is a bit tedious but I suspect somebody smarter than me could speed this up with a script.

Could color perhaps be applied when you name a set of objects? (dropdown like the Size control in V2) I'd even like auto differentiated shades of grey. Of course a "select by name" would then be pretty swell at that point.

thanks
-dale