1. CCW wouldn't have made a difference, it was in a dark theater.
What I initially read about this is that the shooter started in the front of the theater. If he was in the front, what's behind him? The screen. Even with smoke, I'm thinking he'd be nicely silhouetted against the screen. Also, while everybody else would be ducking down or otherwise getting low, the shooter would be standing tall. Then there's muzzle blast, both visually and acoustically, to hone in one.

2. CCW wouldn't have made a difference, he was wearing body armor.
As there are different levels of protection with body armor, does anybody know what type it was? While a round may not penetrate, would it hurt?

3. CCW wouldn't have made a difference, he was wearing body armor.
So it's impossible for a return shot to strike the bad guy anywhere but the chest?

4. CCW wouldn't have made a difference, he was wearing body armor.
The guy had no prior combat experience. I suspect that his reaction to taking incoming fire would be more than a little bit distracting. This would especially be so if, God willing, there were two or more CCWs in the crowd.

5. CCW wouldn't have made a difference because the theater has a no guns policy and was wanding people entering the theater.
Yup, and this is precisely the type of place to avoid - crowded, dark, difficult/slow to exit, and no guns allowed. Ducks in a barrel.

To the extent possible, always go armed or don't go.

TR, excellent point about being stuck on Observe.