Feb 22 2018
I would encourage the adoption of well tested open source libraries for 3D visualization that allow progressive streaming of 3D models.
3DHop would be a perfect solution.
It supports compressed multiresolution streaming of 3D models, supports point cloud and it has already been used in a number of 3D archival projects, like http://zamaniproject.org/ , http://cabinetdecuriosites3d.mnhn.fr/fr/content/cro-magnon-1-homo-sapiens ,
Feb 21 2018
I would say that it is a very important issue. Asking to change the orientation of the original file is not reasonable. The thumbnail creation must be controlled by the user. See for example this file, https://commons.wikimedia.org/wiki/File:Laurana.stl