In addition, there are fake floor blocks that break when stepped on. There is a delay, though. That means that if zombies aren't stopped while on it, it'll break after they are already past. So you'd need to set stuff like that up with something that slows the zombie down right past it so they pause for a second so that they are still on it when it breaks. That being said, such things are one-offs. You might get others that fall into the hole afterwards if there aren't other paths to take but at that point, why bother covering it in the first place? Zombies aren't smart enough to avoid the holes if spikes are flush with the ground anyhow. Not really the best option for defense but it can be done if you're interested in the aesthetic of it.
Regarding CCTV (security camera) stuff... from what has been discussed regarding the CCTV mod linked above (I haven't yet used it though it sounds great and I still might some day), it can really lower your FPS because it's rendering stuff from all the cameras at once instead of only just the single player camera (your own view). If you have a good computer, that shouldn't be too much of a problem as xyth mentioned in the thread for his mod, but for anyone on a lower spec computer, it could be. I'd assume the same issue would also affect it if done in vanilla. They aren't going to want to have anything in vanilla that would add significantly more lag for their players who have lower spec computers.
I would definitely consider trying out that mod, though. Mods aren't bad. I am someone who prefers the vanilla experience in games most of the time and don't use many mods, but mods don't have to change the vanilla experience. Having a CCTV setup isn't really changing your gameplay from vanilla. You just have a monitor to view camera angles. In the end, you're not really going to just sit there and watch the cameras to find zombies. It'll be mostly just a novelty. So not really something that changes your vanilla experience.