A datamined faster curve was retracted, and zones do not scale.
- The experience required to reach 60 matches Classic.
- Wowhead posted a datamine of a faster curve, then retracted it. Blizzard told them the game does not use that file.
- Separately, dungeon kill XP is designed down and first-run dungeon quest XP is designed up.
Source The Sun interview, via Wowhead, and Wowhead's later retraction.