Mikk, I agree with most of your sentiment but some airspace is set up extremely tight on tolerence. Where I work we have four routes all less than six miles apart. As soon as anyone offsets 5 miles is lost.
I don't understand why a supposedly tier one nation like Australia still does not properly utilise RNP 1 and 5 design. It is an enormous place. With little traffic even in the allegedly dense areas. Where I work we run close to 800000 movements with less than 100 controllers. Australia runs about 1.5 million with 800 odd controllers. The system and design in Australia is decades behind the curve.