As far as I know, Nosler has no plans for a bonded PT. The original design uses the front lead core to induce trauma. Part of the reason its a great killer of big game.
Even knowing when I was thinking about it that the Partition is already as close to perfection as something made by man can be, I thought about this same thing. Does a Partition really need better weight retention? Probably not. Things tend to get dead when hit in a halfway correct spot. But I can't help wondering.
The Partition front is designed to blow up and the jacket peel back along the shank reducing the frontal area to help ensure deep penitration. If the tip core holds and the frontal area remains large it will reduce the penitration and defeat the design of the bullet as it is now. I doubt Nosler wants to change the performance of its flag bullet and would probaly design a new bullet if they were to do something along the lines you suggest.