I made a thing.
http://www.fusionroseonline.com/stleditor.zip
This is a standards-compliant ROSE STL editor that takes absolutely no shortcuts in either editing or saving STL files. It is extremely no-nonsense and does not bulk itself up with fancy graphics or UI elements and then forget to properly implement basic operations. Simply put: it works. Well. It is not completely finished yet, and more builds will follow.
I grew extremely frustrated with my STL files becoming corrupted by other editors so I built my own. Hopefully this helps others who've gone through the same frustration. Watch this thread for future updates to this tool.