Yes, it does. But not necessarily for the worse. I have found there are situation where heavily loaded panniers on LowRiders have been the difference between unridable and rideable. Over snow and ice, over angled railroad tracks. In situations like these, the loaded LowRiders are a huge benefit. Obviously I don't make a point of seeking out angled tracks but in my Ann Arbor winters, I used to carry heavy books I didn't need into campus just for the aid to handling.

One of the pluses of LowRiders is that when climbing out of the saddle, the bike handles and feels virtually like the unloaded bike, just a lot more work. No frame flexing, no needing to fight the handlebars to control the bike.

Steering is slower and bikes with less trail (more fork rake and or steeper head angles) are better for regular use with LowRiders. (When I say LowRider, I am including all the copies.)

Ben