I would think weight problems may very well depend on the hands carrying the camera and lens.  This would be an individual choice.   Too much extra weight would bother me at bit, with little cartiledge left in my left wrist...so, there are personal choices to make.

Richard, as you mentioned limits on acceptable aperture, I rarely shoot at wide open and even more rarely stopped beyond  f/18.  Generally, my tele shots are in the f/8 range or there abouts and all works well.

Tom.