Perhaps the delay may be because Ricoh want to:
- further tune and refine all the IQ (optics) and performance (AF) elements of the lens, to make it totally class-leading;
- do further work to closely test and integrate the lens with the new features of the still-evolving FF body - like it's AF system - and existing bodies like the K-3 II too;
- delay the release of the lens because Ricoh are preparing another event soon to launch some more FF lenses alongside the 70-200, and they want to present them all to the world as a set
.