Take some time and read this forum. This issue has been raised many (,many, many) times. You'll probably see some frustration from some of the folks that respond to you.
Many people here have OC'd for some time. There's a wealth of real-world experience.
So, we begin:
"The first is anyone who decides they are having a bad day are probably going to off you first, probably with a bullet in the back of the head, because your their biggest threat at the moment."
Its very difficult to find an example of this in real life for two reasons. One, the vast majority of criminals want easy pickin's and a fast escape. Two, although there are probably thousands who OC regulary its still a very small percentage of the population.
The chances of the rare intentionally murderous thug meeting the rare OCer is extremely rare. In fact, I doubt you can find any actual news reports of a criminal killing an OCing civilian. Zero is pretty rare.
"The second is more realistic, in it removes any sort of tactical advantage of anonymity."
Perhaps you can come up with scenarios where this is bad. I can for CC as well. Here's some reality:
When I OC I am more aware of my surroundings.
When I OC I am always conciously polite. Most people don't apparently notice the OC'd weapon. Those that do tend to be very polite as well. I get more "Sirs", doors held open, nicer service, etc.
There are many personal stories in the True Tales of Self Defense forum where our members simply made eye contact with the BG and a probable crime was prevented. BG slinks away. Your average mugger, 7-11 robber, bully, etc. wants nothing to do with an armed "victim".
CC does not pass that critical info to the BG. You actually have to do a MAJOR escalation by drawing your weapon. To someone that probably has poor decision making skills and a ton of adrenaline already flowing this can have unwanted side effects.
CC does nothing for your gun rights in general. Other people can't see the combination of your gun AND your decent behavior so they never associate the two. All the see is BGs and LEOs and they forget that there's a third group - the law-abiding citizen.
There's a million more, but let's start the discussion here...