Your way doesn't really make sense to me because I feel like, if the Avada Kadavra curse is used against someone, it should kill them regardless of whether they are considered a Horcrux or not. It's true that when the diary, locket, etc. were destroyed their physical forms were still there, but I see that as being the same as Harry dying and his limp body still being there. Anyway, I'm pretty sure that the reason Harry didn't die is because he was Master of Death, I think that is the way that JK Rowling intended it. I mean, that's the whole point of the Hallows in the story at all, is because they bring Harry back to life. I can't remember if he was physically holding the invisibility cloak in the book - unfortunately in the movies they barely mention his cloak at all, which I think they should have done a better job at explaining. And he was actually using the ressurection stone when he died, with his dead relatives all around him, so even though he is not physically holding it in his hand he obviously possesses it. And he is true master of the Elder Wand despite not holding it as well. It makes perfect sense to me and doesn't seem flimsy at all. I don't feel like a wizard had to be physically holding all of these items at the same time to be considered the Master of Death.
But, I do agree that they could have explained all of this much better in the movies. Having read the books first, these conclusions seemed obvious to me and fit with other small details that JK Rowling had hinted at throughout the books. There was much more explanation of wand lore and how you don't have to be physically holding a wand to be its true owner, how there are other invisibility cloaks but Harry's is a very unique one, and more of the backstory of the Hallows. I understand why they left a lot out of the movies, but I think they could have made it more clear to those who haven't read the books. If I hadn't, I think I would be confused about the movie plot.
