Think that the biggest take away for me comparing the first to the second, is that the second had way more build up in its scenes/content! With the bullying line the build up was really nice, you have 3 or 4 events before the big scene, which makes it feel very fleshed out.
The mechanics of the first one were a bit easier to work with and it was more straight forward i think that's what people liked more about that one, but i really liked the point system and the UI of the 5 monitors, think it was a very fresh take on this. If you could "lock" the screen on the monitor you are actively watching that would've helped a lot i think with what most people feel as "clunky".
I like both games for the difference they bring, in terms of setting (family dad spying vs spy looking into lives of his neighbors) and in terms of mechanics ( first CCTV having a more easy to work with environment vs the more complex/things to do in the second CCTV)
I think if CCTV 3 has more of a personal angle again like CCTV1 (either playing as the father/son/mother) with the fleshed out scene buildup from CCTV2 worked into it, adding a combination of mechanics from 1 and 2, you have the best of both worlds.