I like the idea of a changing universal gravitational constant. It is especially interesting if you subsscribe to a sinusoidaly oscillating universe. It would then experience accelerations and decelerations in its expand/shrink velocity as it goes through its phases, and changes of such magnitude would presumably affect the universal constants as well.
Or as tdvance suggests, it might be a kind of jiggling happening in an otherwise calm and peaceful universe.
I have more trouble conceiving of unchanging universal constant values than I do with the changing ones.
OldAlbert