While I have to admit I love the diversity offered by the graves at present, and the bevy of material options make them possible to personalize them to a great degree, I have to admit that I miss the ability to add an epitaph to the gravestone. I know that the idea of adding the cause of death to the gravestone has been suggested elsewhere, but I would rather leave that in the hands of the one building and filling the grave than by some omniscient piece of code. Sometimes we really don't know what killed a particular hearthling's whose corpse we find in the wilds and choose to bring home for a proper burial and I, for one, appreciate that bit of curiosity.
What I would like to see, however, is more elaborate forms of burial. While I don't know that mausoleums are necessarily in scope, it would be nice to have some ornate buildings we can build to house our fallen kin. Perhaps a building that we can add multiple corpses and epitaphs to, or statues that can serve the same function as gravestones. I personally wouldn't ask for any change to the burial mechanics for this, simply the ability to produce a greater variety of ways to entomb our hearthlings.
One possibility I've considered on a mechanics change, however, involves the 'burial barge' idea. Where we create a boat that is set at the shoreline and set aflame, and subsequently pushed out into the water. A funeral pyre could serve the same purpose on land. The purpose of both of these would be to reap some of the benefits of mourning our lost kin, but in a single pop rather than over time. Basically you get a smaller overall amount, but a larger amount quicker pending the complete immolation of the pyre/boat. (several hours at least I imagine).
Overall though, I'd just be happy to have an additional burial option added as part of the smaller patches much as we get additional animals, and the ability to add an epitaph as well.