I would be interested to hear from people who play several random BGs a day (80s) how often does AB come up. If I keep queuing random will I eventually get it? Cant afk out either, dont wanna play 6 hours of pvp.
Total BGs played: 133
Warsong Gulch: 38
Arathi Basin: 26
Alterac Valley: 26
Eye of the Storm: 33
Strand of the Ancients: 10
Note: around 10 of the warsong gulches was played before hitting lvl80.
That leaves us with 26 ABs out of 123 BGs.
EDIT: I do believe the time and day effects what BGs you get. Also the sample size of only my BGs is very small so I might've been lucky with that few Alterac valleys. I usually play at some point between 21.00 and 03.00 server time. I play on alliance.
Yeah there's something wrong with SotA achievements and statistics. I got my "Win sota" achievement after winning strand 5 times, the 4 wins before didnt count for whatever reasons. ;)