I'd say the bracket is alive and kicking. pve is where it is at right now, people are buying t3 and getting their twinks ready. I'd do the same if I were you, and take a look at the current players listing their twinks. Gearing your twink for bgs isn't just about getting the highest tier(unless you are a purist). My advice, is to do the 60s bracket, getting gear and prepping for pvp. Sadly the queues aren't popping for most twink brackets since MOP came out, but 60s bracket has some of the larger changes happening to it gear wise during this expansion and it should definitely help out a lot.
And if you don't like the bracket after putting in the work, its 10 quick levels to 70 and now you have some transmog tiers