I gave it earlier: Use different terminology that won't give the media and punters an attack of the vapours for making the reasonable assumption that a Mayday means a life-threatening emergency. The brains trust in ICAO, when refereeing these little power struggles between ATC and operators, needs to understand the collateral damage being done to public confidence.
But Australia is moving slowly towards a far more effective solution: Turning busy airports into CTAFs because Air relax-everything's-under-control Services isn't doing its job. No separation standards other than 'don't collide' make for very efficient traffic flows.