If you use OS X Numbers or Pages (I don't have or use Keynote) and sync files with iCloud, the old versions had file compatibility issues with the iOS devices, especially the iPhone and iPod Touch. You used to get a warning when opening a file made in OS X on an iPhone that functionality would be lost and suggesting you open a copy of the file instead. But, that meant creating multiple copies of a file for multiple devices.
Now, the files do not change when opening on an iPhone, iPad or in OS X, or when using the iCloud Beta versions (other than some font incompatibility sometimes - so some font substitutions still seem to occur on the iOS side).
The new file formats does then make things better for those who find themselves opeing and editing the same files on multiple devices as you don't end up with an iPhone copy and an OS X copy, for example. You can keep just one file in iCloud and work on it from any copy of Numbers your have.
But, the iOS devices inherently cannot handle anything and everything that a computer could, so it seems some functionality had to be dropped to ensure the file format would remain compatible across all platforms, with the same editing capability on all.
I think petvas' point is valid - that as the mobile devices and iOS get closer to true computer capability over time, you'll see functionality added back in, as long as it remains cross-platform. But Apple is clearly committed to this forward path of integrated home, work and mobile computing and using cloud services for file access, so I am not necessarily surprised by many of the changes becoming apparent in Pages and Numbers.
