No one reads the release notes. When they "downloaded" the OS, it didn't have the release notes.
Although to be fair, it only mentions disk image conversion and RAID. Doesn't say anything about partitions. They will likely add in more features since you can still use many of the features with the `diskutil` command.
Yeah, so many people running alpha/beta developer software without even bothering to read the notes.
Sure, most of the time you'll be fine, but whining about things like this on software that is not intended to be fully functional, but intended for developers as an early sneak peak, to get familiar with the new programming APIs and test application compatibility is a bit off.