As far as I am aware, the footnotes of the NKJV indicate when the word "you" is being used in the plural. Moreover, the use of the word "thou" erects an unnecessary barrier to the gospel. This is the real problem I have with AV people, they need to spend more time focusing on the weighter matters of the law rather than wasting their time in pedantic debates over trifles.
I have two different editions of the NKJV and neither of them have the footnotes you describe. They do, however, possess footnotes which cast doubt on the preservation of the text of Scripture.
I ask you, Mr. Ritchie, to now pick up your NKJV, and to tell me what *it* says in Gen. 9:9 and John 3:7. I could quote any number of instances, as the correct interpretation of Scripture is called into doubt in literally thousands of places by the uniform adoption of "you" for second person pronouns; but these two should suffice to get the point across that the ordinary reader of the NKJV has no idea who is being described when the text shifts from a singular to plural referent.
I don't know why the integrity of Scripture should not be considered by you a weighty matter, especially given the reformed doctrine of sola Scriptura. The authority, sufficiency and perspicuity of Scripture renders this a weighty matter worth much time and effort. The faith and assurance of God's elect depends on it.