I didn't read the entire thread but in regards to the OP's question. My assumption is that you will be able to obtain a physical copy of the expansion on DVD or Bluray disc, dependent upon which system you're installing the expansion on, and the expansion will also be available for digital download after purchasing it and obtaining a code which can be used to register your digitally downloaded copy of the expansion.

I, for one, am hoping that they reasonably price the expansion at $19.99 US or at most $29.99 US. We are paying a monthly subscription fee, after all, and there's no need for SE to rape or wallets by charging an arm and a leg for the expansion. Regardless, of which price they choose....please look forward to it! ( ~.ø)b