1st era: Was of course Viren's era. He certainly had the capability of becoming an ACP, and he did prove so many times, but I think he lacked the vigor that Shivaji sir has. But I really did like his acting, especially "Main beek gaya hoon apne desh par" line. CID was an upcoming show, and if may have looked dull due to a bit of overstretching, that was predominant in the Ramsay era. BP Singh was trying to create the foundation of this great show, with characters coming in and out mysteriously, which might have been misinterpreted as a state of disarray by the audience. Coming to the cases, they were simple yet complex. Less emphasis on forensics and more on investigation. Also what I noticed is that the officers would help locate clues etc, but it was the head, usually ACP or Viren, figuring out who the criminal is etc.
2nd era: Abhijit, Daya, Asha and Sudhakar era: Cases were at their best during this era. Full of excitement, diverse and everyone was equally given a chance, except maybe Sudhakar and Freddy, which I thought was unfair. That was the best and the most hardworking team during the entire lineage of CID. CID PT might have realized that "yeh show ab lambi race ka ghoda hain". They started putting CID officers at risk. CID was not viewed by many then, and the PT tried it's best to make the stories the best, which paid dividends. I felt that Sony did not publicize the show well enough. Also faced stiff competition from the idiotic rise of soaps and KBC.
3rd Era: Daksh-Aditi era: Cases were still quite good but they seemed to be loosing a bit of the charm. Anyways, that was negligible because the cases were still pretty awesome. Introduced the concept of side stories, focusing mostly on Daksh, but also had Daya and Abhijit in it. Manav Gohil was a marvelous actor, but his character was misinterpreted deeply. I was very angry when he said that he gave away secrets to terrorists while dying. Aditi may not have been such a good replaced to Asha, but was much better than her successors. The set and logo also went over a major revamp during this era
4th era: Anushka era: The charm was noticably fading slowly and slowly, yet the episodes managed to captivate the attention of viewers consistently. Many Abhi-Daya danger episodes. Nothing much to say about this era.
5th era: Post-Anushka era: Now the charm was completely lost. Maybe the PT became overconfident that CID hasniw gain popularity and stripped BP Singh off of the story writing, photography etc. Fireworks began engaging in other useless side tracks such as flirting to gain even more popularity. Maybe the PT blew a fuse and didn't realize that such antics completely contradict the purpose of a crime show. People start liking the show, yes, but some of them for the wrong reasons. The plots were senseless and creativity went for a walk(and hasn't quite returned yet). Then came some dummy like officers like Muskaan, Lavanya etc who didn't contribute anything to the show, except modeling.However, of late, they are showing some signs of recovery and the true fans have risen their hopes again.
5