I think Jinbe will live. As I thought Ace would live. I started One Piece only 2 years ago and just as you did, I witnessed secondary characters survived ridiculously dangerous and desperate situation one after another. And when the main character was utterly defeated at Shabondy, it just reminds me of the first encounter with Crocodile or the Cp9. But surprise, after more than 20 chapters, there is still absolutely no sign of the crew. Then Luffy is defeated by Magellan, loses Bon Clay and is forced to fight against Coby and Garp. It was the first time that Luffy had to suffer that much to reach his goal.
But as you said, there are patterns in the serie. Luffy always winning in the end is one of them. Main characters being immortal is another. And yet they were both thrown out the window.
I watch Marineford in less than a week, so yes I was too focused on the current action to make the craziest theory about the future. But even then, I didn't consider that Ace could have actually died so easily.Apparently you don't remember your own reading/watching experience of this scene. Or are you telling me that you've always seen Ace as a talking body bag ?
Ace was created to die ?! Obviously yes, his death indeed brought the time-skip, the tournament and many other things. But let's not get our enjoyement of the plot get mixed with the time-line.
Ace's death became important to the story only after his death, duh! As long as he was alive, he had no reason to die in a show where people don't die.
The death of a relative can lead a character to an awareness and is an obvious plot device, I give you that. But that's the only predictable thing. Is it enough to say "He has death written all over his character" ? I don't think so. Unless you are telling me that he had to die in order to give his fruit to Sabo. Oh boy! So you knew something like this could happen back at Marineford.In summary, characters don't usually die in One Piece. But when they do, it has unpredictable repercussions aside from fanboys crying. This way we can't just look at a character and say :"hey! this guy is going to die for the plot". Call me an idiot if you want, for me Ace's death was a sad surprise. Of couse I thought it might happen, but I was like "no, people don't die in One Piece".
Ace's death became useful post-mortem. And Oda might do the same with Jinbe.
Yes, I did not expect Ace to die. However, after reading his death, the signs are there that he was merely meant to drive the plot forward and die. Obviously you can say that about any side / secondary character, but without Ace going after Blackbeard, the manga would be incredibly different. Ace's death is a climax.
What is gained by Jinbe dying? Making Big Mom a credible threat? She's merely a stepping stone. An emotional moment at the loss of a friend? We already have Ace for that. Ace's death gave Luffy the resolve to not let his friends die. He was going to be there for them. That's why they trained, that's why they waited two years. Killing Jinbe is retreading old ground for a quick emotional punch. And even then, Ace had buildup. He was Luffy's brother. We knew he was to be executed an arc or two in advance. We had an entire arc to save him. Oda is not one for random, shocking deaths. There is no logical way or reason for him to kill Jinbe.