Eliminating the downer of death seems to be the first responsability of any kind of spiritualism.
I have yet to encounter a spiritual world view where death truly sucks, or contains nothing special.
As a kid, I always thought heaven was a very complicated issue, for example, does heaven exclude all non H. sapiens, or does heaven allow ALL living things that have ever lived? Since non-humans are unlikely to be capable of deliberate sin, one would assume that every single individual of everything non-human that ever existed would be allowed in. Since heaven does revolve around sin/no-sin, it seems unlikely fish or insects or lichen or trees will have anything to do with heaven, but it seems unfair to send all dead trees to hell.
in short, it never made sense to me.
I guess if heaven was real, we could check with heaven for The Exact definition of Homo sapiens, since it is the only organism (to ever have existed) that is allowed entry.
A similar problem exists with the whole 4000-year-old-earth idea, where all carboniferous creatures, all devonian creatures, ALL mesozoic creatures, every species of creature that ever existed, lived together.
For example, the North American continent would be absolutely swamped even if we ONLY counted ONE family of organism - the Sauropod dinosaurs, even if we only counted jurassic ones - for example Oxfordian (a time period section of the latest Jurassic) Sauropod genera allready evolved into separate species by the Kimmeridgian (still in the latest Jurassic, but about 10 million years later)
So, a time-period as cramped as 10 million years allready sees a division of a genus into several consecutive species. Add 200 million years to that, and then 3-4 billion...