I don't think they run abusive sergeant and/or did so its hard for them to make efficient trades and eventually shaman overruns them, but just like other aggro matchups it depends on the right card draw, having a lightning storm at the right time certainly makes things easier, but the coldlight oracles help me as much as they help them. Every game has been close and I think harrison has saved me in the matchup a couple of times. They do, and I've noticed a lot of decks doing this now, run 2 doa's so I did put tbk back into my shaman deck. Oh I also run 2 earthen ring farseers because in the early parts of ladder there is a fuck ton of aggro and I noticed my unbound elementals rarely did anything.
If your hell bent on climbing the ladder and you aren't afraid of net decking yourself, just make a zoo warlock deck, its pretty cheap and competitive all the way to legendary. But yeah, I'd focus more on arena until I had plenty of cards.