After testing with some single negatives I bought this awesome plugin today. I think the batch-processing possibility is not the key feature of NLR however the one which will reduce the time spent on the keyboard the most.
Trying to batch process 5 Negs I was puzzeled to see the relatively slow processing. Looking at the CPU load while doing so I figured out that either Lightroom (in my case Version 6) or NLR 2.1.2 itself is not working with a lot of threads. Whereas in this exactly scenario you could create a thread for each negative in the batch job and thus run through a job like this with ease.
Therefore I kindly ask you to take this into consideration for future releases