The inner surface of waders isnt very comfortable on bare skin so I wouldnt wear shorts unless I had knee sleeves or something. Plus they can get a bit clammy if you don't have at least a light weight layer under there.I can't imagine being on water without waders, but I fly fish a lot as well...
The biggest thing for saving weight is thinking of your waders as pants. Now you can take one less pair of pants to offset the weight. (But it's a float trip, why does extra weight matter?) In the summer and fall the weather is generally warm enough to not wear another layer under the waders, maybe shorts at most.
Sure there may be days rubber boots are ok, but when its raining, or you need to cross a swamp to pack out the moose, and kneel and sit in wet to cut it up, you will wish you had waders...
What area are you hunting?I was wondering if I and my buddy going on a 10 day float moose hunt should take light weight waders? My Outfitter just suggested tall rubber boots. I just feel like I should take waders just in case. What are your thoughts guys?