Summary: They realized there was no way they'd finish everything in time for a Xmas release, so they cut out most of the new features.
Personally, I'm glad to see Path of the Titans go (just another grind per alt imo) as well as guild talents (no way they'd be balanced, everyone would just take the same ones anyway).
Very nice to see that 25-man raids can be split up if you don't have enough people the second day, and that raid IDs will be more flexible and interchangeable. Great changes.
I cannot wait to raid the elemental planes.