There might be more than this
as a matter of fact it doesn't bother me that much, just because you don't have to or can't click on it.
nevertheless it shortens the slider to unlock. and no one likes to be shortend ;-)
well well .. we'll get used to it..
the only "problem" might be .. friends who fill up your iphone with silly pictures while hanging out at a bar i.e. ;-)
Even as an iOS developer, I didn't know I could access the camera from the lock screen until this update. I'm glad this came to light, because I rarely use my camera, in the 4+ years I've used an iPhone, I've only used the camera on 10 or 15 occasions.
Anyway, your friends filling it up with "silly" pictures would actually be the last thing you'd have to worry about. If you had someone who wanted to maliciously attack you, for whatever reason and they got ahold of your phone, they could put personally damaging (or even potentially illegal) photos on your phone without your consent. And with Photo Stream and iCloud, they could propagate those photos on a bunch of your devices, then leak information to bosses, the authorities, news media, whomever, that you have these pictures on your devices.
That could lead to public embarrassment, loss of credibility, potential job loss, and in extreme conditions, even jail time.
Granted, it's probably a long shot that this would actually happen, but I think the chances of it happening are high enough that there should be an option to turn this off without completely disabling the camera.