extra weight near the rear depending where/how it is carried does affect the bikes balance and handling differently.
consider, or at least think about if you have the capability to carry the weight in sidebags, and low in the bottom of the sidebags.
weight in sidebags...you will eventually get used to it, and the extra feelings will nearly go away.
weight on the rear rack top-loaded will always cause a heavy, decreased maneuverability feeling. It will affect any emergency handling input significantly, and that heavy slow you down top overloaded feeling will never go away.
yes, some of us have ridden all over the place, with some even riding around the world pack to the gills. But prolly if you asked, most would say even weighted side bags are always preferred to only stacking it high or heavy on the top rack.
....just something to think about