IME, it really depends on the placement of the cases and weight distribution.
A lot of top boxes are mounted on racks *behind* the rear wheel which can lever the front wheel up, reducing weight on it and making steering seem floaty. If the top box is mounted closer to the rear wheel, this minimizes the leverage.
My old GS had a huge 52L Givi topcase and when loaded up, my front wheel would be off the ground while on the center stand. No bueno. I ended up just putting lighter items like clothing in the topcase and heavier items in dry bags on the pillion seat. On our travels, the topcase was half empty just to maintain good handling.
Right now I am having issues with my hard side cases because the pannier racks are so far out to clear the exhaust on one side. Bike feels more unstable than I'd like in the loose, technical stuff. So between the topcase mounted behind the rear wheel and side-cases waaay out to the side, I choose neither and stick stuff on the passenger seat if I'm going to be slightly ADVenturous.
Ironic after spending $xxxx's on hard and soft luggage, this is what I normally do on my ADV bike for dirt trips less than a week (and no camping).