The rest, of course, is history, as Prussia's possession of the Ruhr gave them critical resources to exploit as the Industrial Revolution began.
But I ponder... how would German history go if Prussia had succeeded in its initial goals? If they had annexed Saxony entirely and Frederick Augustus I had been given Westphalia as a kingdom instead. This would keep Prussia as primarily an Eastern European state while also denying it the immediate access to the resources that historically helped it industrialize. Without Westphalia, would Prussia be as able to unify Germany as the German Empire instead of the retention of the loose German Confederation formed at Vienna? Certainly its relations with Austria will be effected, as there is no Saxon buffer state between Bohemia and Prussia now. And, of course, there is the consideration that this Westphalian state itself might have gained some stature in the German Confederation as it became industrialized.
The general course of European history hangs in the balance here, really, as with no German Empire, we will unlikely have WWI, at least not as it eventually was.
And that's all I can think to say for right now. Well, unless I count pleading with Thanas not to bludgeon me with a heavy history tome should I have made any errors in this post.

Edit: Yes, I know, Prussia had Silesia too for industrial resources, but not having the Ruhr would still have an effect IIRC.