What's lacking in Blender are normal Windows functionalities like copy/paste or drag a selection between windows/models, or object groups...
Yeah, but not that surprising regarding its DNA... its a multi-platform software.
I think Blender is the best that you can get for free (as in free beer).
Its not cheaply done or limited in capabilities, but it requires some sort of effort from you to get used to it.
Still, I think for Orbiter, all such tools around are not optimal. What would be needed would be something like a CAD tool (Building models of components, accurate dimensions, abstract entities), with the subject of a video game mesh (which means: limited number of polygons and more options regarding textures or shaders)
There is no tool around that does that mixture, the current situation is that technically accurate video game meshes (like you see in good flight simulators) are the result of both artistic skills and lots of manual sub-milimeter accuracy positioning of individual faces to get components placed.
Or you have more CAD like produced meshes by engineering dudes, that often lack the artistic merit to also look good in a video game, despite having multiple millions of triangles.