As I've mentioned before, I approve of this idea.
Said it then and now again; This is the ultimate move to boost ATS population and quality itself.
I really don't care about what happens to Dragonwrath after the new realm opens, tbh I know that it will die out really quickly.
Fresh realm will also bring more involvement in development. As everyone could see during past few years that main priority was always the upcoming content, as it is now again with DS HC. This new realm as said in the main post will open the gates for everything to have priority since it will be that same "upcoming content".
Twilight Highlands, Vash'jir, Old World content, Polishing (Nopunintended) of the already working content, bringing 4.0 Dungeons quality on pair with 4.3 one and so on.
So, just keep up with the good work.