I think you mean: " shared libs. ". If the lib. is rarely used, then why share it? Statically compile it and it`s conflicting with other libs. problem is solved.Libs should nearly always be put in the standard locations
I looked at ROXapps and didn`t see that they were any better than an SFS. I don`t know the structure of a AppDir, just the app.`s files all in a dir. I guess.
Obviously having all of an apps. files isolated has advantages. But shared libs. and a good O.S. API go a long way toward the reusable software model.