What a normal expansion gives:
-Maybe 1 class
- a complete continent of new zones, That have maybe 5-6 zones in them
- Maybe 1 race
- 5+ new dungeons
- 1-2 New PvP maps
- Occasionally a new game mode
- several raids over the course of 1-2 years until the next expansion
- The same skins re-colored for different raid tiers
- More talents raised to level cap, maybe a few new skills.