You might want to check your facts. The Nu engine family consists of the 1.8L and the 2.0L. The Nu 2.0L is NOT a Theta II, completely different.Look up Hyundai Service Campaign 953 for the rod bearing recall. As for slapping, while yes, more common in the NU engines, most notably the 1.8L, the 2.0 L had slapping issues as well, and the 2.0L is a theta 2 engine, not an NU.
The Theta II family consists of the 2.4 and 2.0T. I know all about campaign 953, I own a theta II powered vehicle. You stated that the rod bearing failure happens because the pistons start rocking in their bore. To date their is no evidence that the Theta II engines have a widespread piston slap issue.