Okay, I made up a new batch with my new recipe in mind. Here's what I did:
Removed the ketchup
Added one small can of tomato paste
Doubled the amount of garlic
Added one more teaspoon of salt
Added molasses, sugar, and corn syrup (Karo light)
The verdict: I added way too much molasses, probably close to a 1/4 cup. For some reason, I was thinking all of the remaining sweetness needed to come from this. I was wrong. I ended up adding corn syrup, which did nothing, then finally, just plain old granulated sugar, which finally brought the sweetness where I wanted it.
My task for next time: Cut the amount of molasses in half, and just add enough sugar for sweetness. No need for the corn syrup, I think.
Still, I think this is a step in the right direction. The ketchup flavor is gone, replaced by molasses flavor.
Next time, I'll nail it.