Recently there has been work on ZeroLink by nopara73 (and others), and 'Ricochet,' which is itself already incorporated into the Samourai wallet. So the question certainly arises: If we think privacy and fungibility is important, why haven't we been working harder on making this happen in Core?
I would submit that now is a good as time as any to revive the open discussion, and provide some code contributions, here:
https://github.com/bitcoin/bitcoin/issues/6568If 2018 is really the year in which this could happen, let's not squander the opportunity.