I was excited to see the info on this new page, but also very disappointed that Battlegrounds were not closer to completion. I really expected them to have battlegrounds in time for release.
On the Horizon
We plan on implementing these features over the next year.
* Player vs. Player Battlegrounds -- Siege Weapons
* Hero classes
* High Level Raid Dungeons/Content
Just to clarify, PvP battlegrounds are in the section above, which is "to be released in upcoming patches". Your quote specifically is about siege weapons being implemented in battlegrounds.
But yes, I was also expecting battlegrounds sooner rather than later.