...abandon the more overtly objectionable racial purity laws, to try and attract a wider level of support from Europe generally....
develop clear and war aims and work consistently towards that
These two are inseparable.
The aim of the war was to push the ethnic boundary of the German race 1,000 kilometres to the east. This involved the murder and removal of many of the tens of millions of people who occupied this vast territory. Over a twenty to thirty year period this area would be resettled with about 10 million ethnic Germans.
Dose any of this sound familiar? It does if you substitute west for east and reduce the numbers somewhat. The vision that inspired this German colonial project in the east shared something with the American ideology of the frontier than it did with Teutonic Knights or the Middle Ages. In 1941 Hitler referred on several occasions to the American example, even declaring that the Volga would be Germany's Mississippi. The American 'conquest' of the west was also quoted by Hitler as an example to justify the clearance of the Slavs.
"Here in the East a similar process will repeat itself for a second time, as in the conquest of America....Europe and not America will be the land of unlimited possibilities."
Now, I am not comparing the implementation of Nazi policies in the East with that of the Americans as they pushed into their West, disease not political and military policies had already done most of the damage to the native populations long before the Americans pushed west in numbers, but the Nazis clearly saw parallels, and some justifications, between the two.
Be very careful when characterising one nation or culture as more prone to such radicalisation than another.
As for the Slavs, well, they would survive for a while as worker-slaves, both on the land and building German towns and factories in the new territories, but eventually they would be replaced by Germanic people, as Himmler explained at a meeting of senior SS leader in the summer of 1942.
"If we do not fill our camps with slaves - in this room I mean to say things very firmly and clearly - with worker slaves, who will build our cities, our villages, our farms without regard to any losses, then even after years of war we will not have enough money to be able to equip the settlements in such a manner that real Germanic people can live there and take root in the first generation."
The remnants of Slav race, the majority having already been 'removed', would survive in The Greater German Reich for only as long as it was useful to the Germans.
In Hannah Arendt's famous phrase,
"the banality of evil".
The budget for Generalplan Ost was initially set at 40 billion Reichsmarks, but Himmler soon raised this to 67 billion Reichsmarks, more than the combined investment in the entire German economy between 1933 and 1938. It was the raison d'etre of the German war.
Steve