Re: This is a deliberate feature and it's because Apple cares.
That's likely because FreeBSD is designed so that you very rarely need root. I've been running FreeBSD and TrueOS for about three years now and I can count the times I've used root on one hand.
Thing is, last time I had to anything in the terminal for OS X and needed root, it took me awhile to figure out how to enable the root account as Apple has it disabled by default (or at least did a couple of releases ago around Mavericks) which is usually smart, most users have no need for it. It shouldn't be that easy to escalate privileges in any software. This is the kind of trick that I would have tried back in High School just to see if it'd work, trying root with a blank password, then with "password", and then "administrator" just for shits and grins.
Maybe Apple should hire some decent QA people and give external power users a reason to actually test for them. They won't because they're deluded into thinking that they're perfect, and a lot of that is because of Jobs' blamelessness ("You're holding it wrong"), Ive's very clear desire for form over function, and Cook's issue with keeping quality high so that they can justify their outrageous prices. But it'd be a really good idea.
Thing is, even despite this, I still want a Mac mini whenever they update the hardware. It'd be nice to have a UNIX that I don't have to constantly fuck with to use every now and then.