Please, keep going, you can imagine as engineers, we don't have enough information about your workflow, or insight on how architects are using AC in general.
we architects use ArchiCAD as a 3D modeling and documentation software. Nowadays we cant manage complex, high poly exterior scenes (vegetation) in Archicad, so we need to adopt other software to achieve high-quality 3d images. Without corona proxies, there is no clue for general adoption of Archicad as a rendering tool. Corona has the potential to import all the advanced rendering goodies (proxies, scattering system, procedural textures, batch renders, distributed renders,...) to Archicad. Almost all of these features are a must-have to compete with any traditional rendering environment.
Ideally, corona proxies should behave exactly as GDL objects do, id est, in particular with the ability to represent various geometry entities depending of context (we need a tree to be represented in a particular manner in a plan view, and no, just a 2D projection of the 3D geometry will not work, usually a representation of a vegetation or a furniture is dictated by some standards, not an artistic option). When looking at Archicad 3D views, this proxies should be represented in a stylized manner (probably low-poly) and it should be represented high-poly when rendering (well, this is the main reason for using proxies, a responsive work environment. Sure, also low ram memory and blah-blah...)
Hope if this clarifies and (this) architect point of view.
thanks and keep on the great work!