Most people who've replied seem fixated on the North Atlantic. I understood 410 to be saying it should be introduced everywhere else as well, where most airways are two way and a half mile offset would set opposite direction traffic apart by one mile, (which would have saved the pax and crew of the 737 in Brazil).
Personally, I can't understand the resistance to the idea. I'd much rather see opposite direction traffic fly past me to one side than right over or under me.
What's the problem of being a half mile from overhead the aid when flying overhead IF YOU"RE ABOVE FL200? With 410's suggestion, the offset wouldn't be activated if you were below 20,000', like when you were doing an approach, the only time it would matter a damn if you're absolutely overhead the aid or a half mile to the right of overhead.