Well, I meant more Sanzo worrying about it than it materializing, but also something more along the lines of Kou getting held up for some reason - Nii screwing with him, Gyokumen Koushu finding out, or whatever - rather than him deciding not to stick to the bargain.

I agree; Sanzo probably would have made it with Goku. But yeah, he probably wouldn't have made as good a parent (and when your basis for "good parent" is Konzen... yeah.)