My main reasoning for ordering an S1RII: I want a single body that can do hi-resolution landscape, wildlife that moves (for which the hi-res sensor is also useful), and astro.
Secondary reasoning: Better shadow recovery than the S1R, and all the bells & whistles of the new body & app.
What would cause me to cancel the pre-order: Do I want 60 MP more than I want speed? Do I want to switch to MF?
Also: If I convert either my S1 or S5 to full-spectrum for astro, that eliminates one of the reasons for buying the SR1II, since I would then not use it for astro. In that case, do I just accept the AF limitations of my existing S1R for wildlife, and drop the pre-order for the S1RII?