Last time i heard of the "DOTA BG" it was scrapped and wont be included.
They said they still wanted to add it in MOP sometime.
We do indeed, the biggest problem with releasing this battleground is that it requires some new tech, however we would very much love to be able to release the DotA-style Battleground during the Mists of Pandaria Life cycle.
Regarding this particular battleground becoming an eSport, I see that as all depending on the community and the support that it is given. I personally would love to see more World of Warcraft eSports, I find myself spending loads of time watching streams and videos of arena and rated battlegrounds...they are ridiculously entertaining! ^^