I vote against as PHP kind of doesn't work this way - you've got
autoloaders, automaticly included files, lots of magic etc. Limiting it
to the explicitly (inclu|require)ded files is not a good idea.
The only thing I can think of that could be usefull is to add some kind
of directory metadata that files in this dir only have content assist
from these directories (and a list or regex to select them). I'd prefer
through that PDT developers focus on more important things first.