be sure to include the full picture when thinking weight... including yourself, your pack, your shoes, water,...
Well, having a lighter camera doesn't force you to take more weight with you, does it?
But all in all, you're very right to point that HUGE weight savings may be made starting with "normal" mountain gear. Lighter shoes, proper clothing, smaller pack... There are dedicated resources on the net to help with these choices,
http://www.backpackinglight.com eg.
About the camera, I'll throw another component into the mix : the viewfinder.
I really have a hard time composing on something other than a ground glass.
Though I did try to take a small Ixus (aka SD800) with me, and though image quality was mostly-sufficient-if-not-stellar once the CHDK made it shoot raw, I just can't see what I'm photographically doing when composing on the LCD. And of course, the keyhole mimicking an optical viewfinder is way too small to be usable, and you don't see what the camera is doing with autofocus and autoexposure while trying to see something through it (and they do wrong things, by default).
So, even if I may be a weight fanatic in some cases (I think more and more of spending more than 1 euro-grand on carbon shoes for backcountry skiing eg, or fell in love with the beer can stove concept for that weight reason), I just keep my DSLR while hiking and backcountry skiing. My goodol'Rebel, a 10-22 (and, not always, a 50/1.8 and/or a 55-250IS) make a relatively small and convenient package.
For that reason, I'd suggest trying to get a smaller DSLR : entry-level APS-C or 3/4rds, with lighter lenses (and no tripod when not needed).