I've had zero issues with my NightHawk cable, it's two very high-quality cables (L&R) running side by side within a weave. If you simply run your fingers gently down the length of the cable you'll keep it nice and flat and it won't twist.
Now with regards to connectors/connections, I can only say that I've never had any issues and these are my go-to headphones.
As far as the end tarnishing, silver will tarnish, I use Cape Cod Metal Polish (comes in a can with wipes) from Amazon and in a few seconds of use the plugs look bright and shiny/like-new again and stay that way for weeks and weeks.
AQ could have gold plated the plugs to help prevent tarnishing but then I think they set out to make the best sounding cable they knew how to make. I would take this cable over the newer one that you can bend over and over again as that probably means (I don't know this for certain) that AQ moved to a multi-strand wire and that's not usually the way they go since they are big believers in solid-core cables.
Of course, YMMV