Well, even without the extermination camps, Nazi labour camps were pretty grim places. That, BTW, is what they did with their 'undesireables' - put them into the KZ. Certain areas of camps during wartime could have attrition rates of over 1% per DAY from starvation, disease, and dangerous labour!
You also have to keep in mind that the Nazi leadership was perfectly happy to kill millions of people outside the gas chambers. There is a particularly ghastly piece of film from early 1941 where a German plane flies low over a sea of Soviet prisoners - allegedly somewhere in the region of 500,000 men. The horrible thing is to realise that four weeks later, not one of them was still alive. So death rates would still have been terrifyingly high.
As to the Nazi government's policy, I assume they would have continued as before - starvation, ghettos, pogroms, the occasional mass execution, massive forced labour etc. Incidentally, I don't believe the death camps were ever a long-term plan. Most Nazis simply didn't care what happened to Jews and other 'subhumans'. Killing them factory-style must have struck them as hygienic. If there had been other options, they'd most likely have taken them, too, or at least considered them.
The real clincher comes after the war. I think it would have made a world of difference for the debate in postwar Germany. Without Auschwitz, the enormity of Nazi crimes could be considered comparable to those of Stalin. That means much more credibility for right-wing revisionists and demands for 'the borders of 1938' and similar c**p (sorry). Equally, support for Israel might have been lower and Antisemitism and racism in general remained more acceptable in the social mainstream.
