Fangtooth posted an additional change in 1.7; the level ranges will be changing to the far more sensible ranges of 20-29, 30-39, 40-49, 50-59, 60.
Fangtooth wrote:
In the upcoming patch, we will be changing the level ranges of two Battlegrounds. Warsong Gulch and Arathi Basin will now be level-banded as follows:
- 20-29
- 30-39
- 40-49
- 50-59
- 60
This change makes the level ranges much more, er, sane, as several powerful abilities are gained at level 40 and level 60, which heavily disrupted their brackets.
Presumably the Alterac Valley range will remain 51-60.