"could be" is all very well, but for the people using bitcoin right now, it needs to be "is".

How long do the delays have to be? Does it matter if the recipient isn't using a randomisation service? Etc? I'm not saying these questions are unanswerable, it's just that they need real solid thinking done on them, which (as far as I know, which isn't very far) hasn't really been done. And then the answers need implementing.