I seem to remember it being said (before Pro was released) that a product's SKU would be the Product ID and appear in the Product's URL. The Product ID wouldn't change as products are moved from one category to the next. I've noticed, however, this isn't the case.

I have multiple web sites where I promote my products. Each time I move a product from one category to another, I have to change the URL to that product on all of my web sites.

Rather than a Product ID being sequentially and automatically created, will SCC Pro eventually include the SKU as the Product ID so it remains the same when moving between categories?

That was never a feature in the the software as the SKU number has no relevance in the product URL. If you move a product between categories, the URL will change because it is now in a different location. Right now, there are no immediate plans to change that as it really hasn't been a big user request. If we see more people wanting something like that, I am sure we would consider it.