Mr. Mike
It's a very good question. I believe some of the episodes were weaker starting in Season 10. When Does A War End? and A Short Walk On The Longshore springs to mind. Season 9 was a very strong season. 200 episodes into the Series...Double Exposure. I believe Double Exposure is 1 of the best later episodes in the Series. Some people have astutely brought up the networks limiting too many violent scenes in an episode on TV. This was in the late 1970's. It would hurt a crime show like HFO 🌊. I believe The Skyline Killer Season 11 is a good example. The Serial Killer was very elusive and intelligent leaving a trail of victims. They could have showed up close and different damage and wounds to the bodies. More graphic but they didn't. Earlier HFO episodes showed more violence like in All The King's Horses and Samurai. No doubt, Chin Ho murdered and thrown out of a vehicle like garbage outside HFO 🌊 Headquarters...It's very shocking and horrible. They easily could have ended Classic HFO 🌊 after A Death In The Family Season 10 Episode 238. McGarrett and the HFO 🌊 team investigating Chin's death and capturing the perpetrator. Honoring a great detective.

Bobbi makes a good point about William Smith. It would have been interesting if they brought him on say late Season 9. His style of crime fighting clashed with McGarrett's. They could have had some good back and forth heated conversations but ultimately solved cases and respected one another. That might have given some new adrenaline and energy to the later seasons. Losing Chin Ho at the end of Season 10 and Danno after Season 11...That's difficult for most series to endure. I think Season 11 and Season 12 have a few good episodes and Duke earned some more screen time. DUKE was underrated and definitely a solid detective. He had many years of experience as an HPD officer.

I don't believe there was 1 exact moment where HFO 🌊 jumped the shark. JC