You know what I, as a 60, miss the most from levels 1 to 59?
I miss the sound you get when you discover a new area and piece of the map fills in.
Such a nice sound. The sound probably doesn't play at 60 because it's tied to the experience gained for the discovery, and you no longer get experience at 60. It's a pity though. Hopefully it will return when the level cap goes up.