You guys need to relax. There isn't anything necessarily wrong. If you have some understanding of computer architecture or operations research you probably know a strictly sequential model, which is the old INS processing model, is usually not performant. To enhance throughput in a complex system, which USCIS is, typically you need to look at the whole pipeline and try to process whatever you can, regardless of the sequence. I am conservatively optimistic about the fact that NSC is not strictly adhering to RD/ND sequence, this shows they are trying to optimize their thoughput in some way.
Of course this is not "fair" to everybody, but well, I am too old to believe in "fairness". It comes down to this: one person's loss is another's gain. I am also disappointed some lucky guys/gals whose PD/RD/ND are all later than mine got their dear cards while I am still whining on this forum, I do find some solace in the thought that my suffering in whatever small way, contributed to their joy.
Also, coming from a politically suppressive land, I am kinda impressed as well as amused by the sense of entitlement some folks manifest towards the greencard. At the end of the day, this journey of endurement that the GC process is, is our own choice.