Maybe this is an extreme point of view - but don't you think it's inconsistent that you can't have a parent slot 'implemented' as a method? OK - so it might be a bit slow - you'd have to call the parent slot method(s) for an object for every message it received.
Does anyone agree?
No, I don't think it extreem: it's also bothered me for the very consistency reason that you point out.
Should the method in the parent slot be evaluated when a message lookup has to go through that slot? If so, why? And if so, what if that method sends subsequent messages to self that don't match directly in the receiver? Infinite regress city.
But maybe the method in the parent slot is not evaluated when it is looked up through (new verb form there). If not, why not? And is there some utility to having parent as a message be different from parent used in lookup?
These thoughts have always bogged me down.