Surely we won't know till the next update?
Apple doesn't say how much the required space was reduced, but we were able to install it on a 16GB iPad mini that only had 445MB of space available. Earlier updates required using iTunes on a Mac or PC to update this iPad.
No this update required less space to install. The key being not the size of the update but the size of free space required to unpack and update the iOS while its running. That was the issue that was addressed.