I would say of all the lore events this one was probably the best one Riot had done because it actually carried over into the game. The Ascension mode was pretty good as well. I think it's time for another "death of" though to shake things up again.
The problem I see with killing champs is that as of now most champs didn't have much screentime,thus it'd feel like a waste of character.
I mean when GP "died",pretty much no one believed he was truly dead,because we hardly got to know him and announcing champs as dead only to reveal that they survived a few days later would simply cause people to assume that champs will never die in the story.
The GP "death", while cool in a narrative sense, kinda fumbled in a few ways.
First off, like GreenLore said, nobody thought he was actually dead. He had JUST been reworked. We'd just been introduced to NewPlank at the start of the event. It's kinda like every time you hear in comics that Batman "died" or Captain America "died". They're gonna be back. If you do it too much, it just becomes something people kinda roll their eyes at and go "Oh, THIS time they DEFINITELY mean it."
There was also the backlash to disabling him in game for Lore reasons. Since he was turned off for a few days, and Riot kept up the facade of "Nope, he's totally dead.", some third party websites were talking about how League was making a bold move by "deleting a character". And then someone brought up you couldn't get a refund for him or his skins. Then THAT turned into "WOW WHAT THE HECK RIOT JUST REWORKED A CHARACTER TO SELL SKINS THEN DELETED HIM???? WOW WTF????" And of course, he was back not a week later anyway. And that's not Narrative's fault, that's people jumping to conclusions. So it's kind of a risky move.
Now, I agree with you, I loved Burning Tides, I think it's the best Lore event Riot's ever put out. But if they do another death, I think they should probably not disable the character this time, and maybe actually make it stick. One of the advantages of having a Lore/Game disconnect is that you totally can do that if you want.
It would be cool say this is just a example 
finally died in battle the way he wanted fighting in the Freljord Civil War, Now say someone who admired Olaf Took up his axes and carried on his legacy but because it is someone new his kit, look and lore would be a good rework idea
Yea we do, It brings lore alive and so far this is the only moba that can and has intertwined lore and gameplay. I'd love to see more
If anything just fix or redo the lore loft the champs that mentions the league or summoners because that seems to have just dropped off the face of the earth
