In some moments, the handling of my bike while loaded has been better than unloaded. Definitely slower steering, but planted!
You touched on it a bit here and maybe you'll delve deeper in the follow up articles, but securing your handlebar load is key. I prefer as low as possible taking into consideration fork travel and cable routing. I use a Rockgeist Barjam harness which is similar to the blackburn harness you use and it accepts almost any dry bag. But the best part to me is that it uses voille straps that go around the fork crown. Bag is not going anywhere! I don't know if that's unique to the Rockgeist design, but def worth looking into modding this for other bar bags if not already a part of the design.