They've been working on the game for what, 5 years? How much more will be finished in 8 months?
Im no game expert or anything but id assume they have been doing stuff like you know.. lore, thousands of quest designs, artwork for an entire world, PvP system, classes etc for alot of those 5 years.
And now they are working on all of it ingame tuning things as they get tested since there is a limit to what you can test internally, I mean MMOs need ALOT of time everything in the world has to be coded, designed, everything you see in a game someone made its not just copy paste for 5 years you know?