Hi Chams,
I agree with you in regard to WW2 shaping Speer. I believe the propagated impression of Speer's armaments miracle was quite fallacious, with Speer being credited just because he was in charge. However, I'll play devil's advocate for the other two points.
In terms of his architectural career, I would argue Speer certainly shaped the event more than the event shaped him:
Between 1933-1941, his technocratic architecture was influential in consolidating Nazi power on a national and international scale
- His architectural capabilities were ultimately useful in shaping economic revitalisation following the aftermath of Treaty of Versailles through his work as the director of The Beauty of Labour
- His creations like the Cathedral of Light were regarded as "instant propaganda" by Hitler himself. He was quite influential with his theatrical twists on architecture
- We can also see this through the symbolisation of Nazi iconography at Tempelhof, turning May Day into an event appropriating the Nazi narrative, and the autumnal harvest at Buckeberg
- His appointment to GBI in 1937 was also important in him being able to shape international events. I would argue that without Speer, Germany would not have won gold at the World's Exposition
- At a more minor scale, he also served on international panels to decide professorships around Europe
In terms of the Nuremberg trials, I would simply argue that, by painting himself as the 'good Nazi', he was able to influence the jury, subsequently allowing him to escape the death penalty. Obviously, his claims have been proven disingenuous, which further demonstrates his ability to influence/manipulate this event.
Speer certainly wasn't apolitical, but I believe he was merely an opportunist with influential behaviour. If anything, he himself was only shaped by his childhood relations - bullying from brothers, unapproachable mother/father - that turned him into a cunning leader later on down the track.
However, this is only how I would argue it! I'm sure you can spin it both ways.