I think the general idea of losing your items on death gives player's the feeling of danger, and often invokes fear into most players. If you kept your items when you die then all care would be lost and the fun and fear would be wiped away.
Never for any of our Agrarian Skies servers.. The mod-pack was meant to be hardcore and we are even lenient to some angles. While dying and getting back onto your feet may be a annoying and painful process I feel it is also one that makes Agrarian Skies more enjoyable. If we enabled Keep Inventory on Death then there would not be a reason to play the game careful and people would/could simply jump off the edge to regain half hunger.
I can see were you are coming from and think its a good idea now you have said it. It also learns you to be more careful when near the edge and to use that SHIFT button.