So, now Hermione is by far the most immortal person in the universe. She has troll's and unicorn's powers and Voldemort's Horcrux 3.0 network. (Although she doesn't have physical possession of the Resurrection Stone, at least not yet. I wonder if she will be able to sense all of Voldemort's horcruxes right away when she wakes up, or if she would need to know some extra spells for that.)

A troll heals by continuously transforming into its form. Does this mean Hermione will never age, because she will always transform into a 12-year-old body? On the plus side, she wouldn't fear old age...

Also, if Harry (or anyone else) defeats Voldemort somehow, he would get the Philosopher's Stone. And unless it has a limited store of energy, he will have defeated Death at that point. It would feel really unsatisfactory if he defeated Death just by stumbling across an artifact that always had the power to defeat Death, but no-one ever bothered to use it for that purpose...