If someone's dying wish is to, well, die, then it's probably a good idea to make sure there aren't any necromancers or brain-uploading robots or anything like that around first. They might not be happy to find out later on that something went wrong.
If you give your players a quest to accomplish, it's too easy to spell out all the requirements explicitly. Instead, try just dropping vague hints as to what needs to be done.
For example, they might know they need to retrieve a "blue rabbit", but they have no idea what sort of rabbit or why it's blue, or if it's a specific legendary blue rabbit, or just any old blue rabbit.
They might not even know that "rabbit" is a corruption of a word in an ancient language, "rebett", which actually means "gem", and not rabbit at all...
What some players see as unnecessary effort can be bread and butter for someone else. If someone else is enthusiastic about character backgrounds, consider working with them to develop your own. If a player has a flair for plotting or bad guy motivations, recruit them to help craft an adventure (of course twisting things just enough so they don't know exactly what will happen). Use the skills of players who like doing certain things to expand everyone's fun.
A lot of things depend on how you look at them, especially things like human motivations.
So why not set up a quest that can only be completed by the correct motivations or emotions, rather than by simply finding the right object or killing the right monster? There are elements of this in fairy tales - needing to to break the curse by finding true love - which leave room open for creative interpretation (see Frozen for a good example). There's no reason you can't borrow such elements and insert them into a more serious or gritty campaign.
Imagine how different the story would have been if Dorothy could never return home until she accepted that she would have to live in Oz forever. Or if Frodo couldn't destroy the Ring until Sam let him throw himself into the fires of Mount Doom with it (and he skipped third dessert).
The escape through the self-destructing villain's lair is a classic element of films going back as far as Dr No, the first James Bond film.
When a hardy group of PC heroes successfully infiltrates a dungeon and defeats the final boss, try having the dungeon start collapsing around them. Mooks and minor monsters can scurry and flee all around them. The heroes' priority should be to get out before the place caves in and lava fills all the open passages. Fun and excitement for all!
One of the perils of demonstrating something using models is that your players can be so much pickier about it than if you just describe what's happening. With a model, you're stuck.
With a description, you can just change what you're saying every time they point out some inconsistency or physical impossibility, and pretend that's what you meant all along.