Scripts and environment variables are an ugly hack. Environment variables are dynamically scoped and will cause problems, if you don't care to suppress them from being inherited by child processes.
Suppose there are two installations of app. One is the system one, and one is locally installed by the user. The user overrides LD_LIBRARY_PATH when invoking the local app. Suppose that that app is used in such a way that it invokes the system-installed app; that could then find the wrong libraries due to the LD_LIBRARY_PATH being inherited.
A program must simply know where its exact pieces are, all by itself, without any external tricks that could influence more than just that program.
Search paths (all of them, including PATH) should be left to the user, for arranging the system; the user should be able to manipulate paths in arbitrary ways, yet the application shouldn't break as far as being able to locate and load its own pieces.
