Now that it is possible to have a single product containing certain variations with a fancy product designer, and certain variations without, it is necessary to have better control over when the Add to Cart button is shown. The global Customization Required option hides the Add to Cart button for the entire product, regardless of variation options. Ideally, the Customization Required option would be "smart" enough to only apply to those variations that have a fancy product designer assigned.
Thats already possible with the latest update. The "Customize" button will disappear as soon as you select a variation without a FPD product.
I think there is some misunderstanding in what I am requesting. If you have Customization Required set to yes, variations with an FPD product have the Customize button and no Add To Cart button. This is good, makes sense. If you select a variation without and FPD product, the Customize button disappears. This is as you mentioned and is good. However, for that variation without the FPD product, the Add to Cart button is still gone. So there is no way to buy this particular variation.