I have a question about current battlegrounds level and gear scaling, since I've been out of the game for awhile. At one point, Blizzard used to scale gear item level (and corresponding stats) from the bottom of a bracket to the top of a bracket. At another point they dropped that, and simply scaled the character so that the character's base stats went up, but the gear stats didn't change. Where do things stand now?
After about three hours of preliminary research in WoWhead SL Beta exploring gear for the 20-29 bracket, it's looking very likely that all of the best gear will either scale from quests and dungeons, or drop from raids requiring level 27 (the old 70 raids). Basically, all of the gear from levels 71-79 got squished into levels 28-29, so it's very likely that socket gear will rule the bracket. While this isn't new for 70-79, what IS new is the mastery stat getting pushed back so that the whole bracket has access to it now, and (ironically) the stat squish increasing the impact of sockets.
Depending on how much Blizzard squishes gems (and whether Blizzard changes gear ilvl requirements for certain gems), it's likely 27s will see the same overall stats as 29s in battlegrounds. If ilvl scaling in BGs is a thing, then it becomes likely that the optimal level to play in 20-29 will be 27. Of course, so many variables make this way too preliminary to even guess, but I would love to see one of the old-school brackets retain peak status in the new brackets.