In my experience, those are about as useful as telling your dog about the bug. Complaining on HN has a slight possibility someone from Apple might actually see the bug, and fix it.
I'd disagree, I've filed probably 15 in the past 7 years for obscure bugs and all of them were fixed. They don't respond and the fixes take a long time, but I'm pretty sure they are listening.
Not that this will instil a huge amount of confidence, but I filed a bug about a XNU kernel syscal that returned the wrong error code. They shipped a fix two years later and closer the ticket.
If it was just changing a constant (which is what GP implied), that would probably not constitute sufficient creative output to be subject to copyright.
I would be more inclined to file them if I didn't have to consult an independent third party (open radar) to (hopefully) see what's going on with the radar referenced when one gets closed as a dupe. The more you make it a chore to file or track bugs the less likely I am to bother.