I'm sure this is misconstruing it, but this sounds a lot like putting less skilled people on the high traffic, high capacity aircraft routes.
No. Every job in ATC (tower, approach, enroute) is different. Every sector, tower or TCU is different. They all have there own unique challenges and each controller is trained to handle them. The situation I describe is what currently happens to the controllers handling the J curve. They don't routinely separate procedurally. Try asking them for a clearance without a transponder during a busy burst and see what happens.