Why don't they release the passive tree early?

I've always wondered about this - why not release it early so fans can plan their builds and fill in the time before release?

I guess it's because they are still working on it.

Aye I've thought about that and I can see why maybe releasing an early version with last minute changes could be problematic. However I have to wonder how much they are actually drastically changing it right up to the launch?

Drastic changes, doubtful, but there may be subtle changes. They might move a node ever so slightly in a direction to make it or not make it compatible with a jewel's radius, for example. The numeric values might be slightly tweaked. They may add/reduce a small passive inside a cluster.

We should see it Thursday but im hoping for tomorrow. They release the predownload thursday so people will start data mining it then.