I agree that "within 3-4 weeks after Nost PvP" is far too long for the new realm. I understand that the Devs want to ensure the Nost Legacy and through the old servers reduce the new servers population. But I don't think it's going to work as they planned it. People already decided on what server they will play and it seems that most of them will start on fresh realm and eventually raid on old realm (if they have a lvl 60 char on Nost)
I honestly would recommend (and do still hope) to launch the fresh realm during Christmas times. Either people have time to play or they are away with family, friends etc.
Considering how well the 2 stress tests went I'm eager to see the result with the actual realms.