The best we can realistically hope for is that Nissan will upgrade future model year Xterra's. With luck, the parts will swap, but if the right SUV comes along, I'd just buy it. I do have flexibility as I have not sunk any significant mod money into mine.
No way that they will pay reparations of sorts to current owners. Some beancounter in the underwriting dept. in the bowels of nissan corporate figured out that warranty costs on 4x4 drivetrain would be less than the profit made by selling cheaper/lighter components (x 400,000 trucks or whatever). plus the light parts helped them to squeeze and extra mpg out of the truck to help out with their corporate avg feul economy rating as mandated by the gov't.
like I said, if the product improves, then good on nissan, if not, vote with your wallet.