I don't know why, I understood when they announced the extra two weeks per patch that this was in order to make 6.5 shorter by those extra weeks, so they would be releasing 7.0 in mid to late spring.
Well, I guess it gives the staff a bit more time to breathe.

Now that I'm only back every 45 days to keep my house, I don't mind that much as I play whatever came out during my absence and I have dropped savage raiding, but I do feel sympathy for anyone playing daily until 7.0, especially as .5 patches usually aren't that great content-wise.