When I was operating King Airs in the Carib, I listened to many different airlines on Centermer and other frequencies. And 99.9% percent of the time ATC is good and attemps to plan ahead by asking traffic to descend or climb when on converging tracks, same level. And 99.9% of the time the crews comply politely with no quarms. Obviously the climb request sometimes cant be done due fuel implications, and its the luck of the draw who gets called first to do so or asked to descend. But hey these guys have a job to DO and someone has to give out there, not ATC.
In Australia theres alot of OCTA flying no radar only procedural. And its up to the Pilots in most cases to organise there own seperation. Common sense must prevail. Its Airmanship actually really, good airmanship should lead to good proffesionalism.
Regards
Sheep