It hasn't been that unnoticed. I'm getting kind of bored of the articles on NFL.com stating the obvious about how the D is playing well, which anyone who cares already knows because it is quite an easy thing to notice. It's not like if an O lineman is playing really well and making a big difference, then yeah, a lot of people would need it pointing out.. but an entire D is pretty obvious and it's kind of annoying when people try to look smart by pointing it out.
Also, kind of a coincidence that the whole team (not even just the D) started playing well just at the time they instated a really good leader at QB. That's one little coincidence that has been kind of unrecognised by the people saying it's just the D.