So you don't want new people to ever be able to experience the older content? People ran that content synced and got what they needed from it. No one wants to waste time running it synced. So you'd basically have tons of dead content. At least with the unsync option it keeps people doing it. So the new folks do get to at least go into the instances and see the content, if not all the mechanics. If you don't want to unsync, then you can put together a PF and find like-minded individuals. But if SE did what you're asking, it would just die, since people do not want to run this content synced any longer.