I'm going to maintain a point I made ages ago:
Death times should be a function of 3 things: Game length, Player level, and most importantly number of player's own deaths.
Why isn't the last point considered? I don't care if there's an annoying fed opponent and your whole team is trying to come back and finally kills him late game and you want him to have a high death timer so you can accomplish a lot while he's dead. That's not fair to him. If someone has made it 45min without dying, why is their first death a 60 second timer when everyone else's first death was like 8-15 seconds?
I have literally lost games on my first death. Made it to late game with a score like 8/0/11, got killed for the first time, and lost during the 60 second death timer. That was back in season 4, and I thought it was stupid then, and it's only gotten worse now.
If you're not dying all game, your reward should be shorter death timers. You can even reduce kill xp and kill gold to balance out the snowballiness. This would make more exciting competitive play. It would make the game feel more balanced. An early kill is just as important as a later kill, as the early kill is needed to start racking up their death timers.
I see a system that's sort of like:
Base timer of 5 seconds
Increased by 0.25 seconds per minute of gameplay, to a maximum of 20 seconds
Multiplied by (1+ champion level / 10) (so maximum 2.8 * 20 seconds = 56 seconds)
Multiplied by 0.5/0.75/0.9/1.0/1.05/1.10/1.15/1.20/1.25 capped.
So even at the 60 minute point, if it's your first death it's only 28 second timer. If it's your second it's 42 seconds. Fourth is 56 seconds. 9th death and onwards is the maximum of 70 seconds.
Maybe it needs a few tweaks - it seems a lot more fair to me though.
It ALSO has the added benefit that stomping someone actually means something. Currently if say Vayne falls really far behind but her team does alright, she just comes back huge and is still a huge threat late game. Already having 9 deaths would make her death timers a lot more punishing.