RFC: does ld.so.preload still make sense?

[Adhemerval Zanella Netto]

As comment suggests it should be only used for emergencies and testing,
as it is a non-configurable file path that works even for SUID binaries
(there is no way to disable it nor to change the its patch without 
patching glibc).

It is also not properly document on the manual, although man-pages does
have an entry with a proper explanation.  I am not sure it should be
considered as a security liability, however it is an extra performance
hit on *every* program execution for a very specific and not really
deployed feature.

Is this still useful in current scenarios, as debug tool to fix 
misconfigured systems? Or should we remove it?