Derek wasn't responsible at least not directly. He certainly contributed to the racial tension including heavily influencing Danny's perspective up to that point.

It's kind of implied that the kid who shot Danny was getting into a gang and that was part of his initiation. Which makes it mostly just a tragedy since Danny had just had some revelation and has now been killed over something completely trivial.

Well for one thing some of the things mentioned couldn't have been done earlier in the war. Pillaging other countries couldn't happen before those countries were invaded. The heavy use of slave labor pushed by Speer couldn't have happened without that pool of slave labor. And so forth.

And despite all that germany was still being heavily out produced by the allies.

No idea how it would hold up on a second rewatch but I didn't get around to watching it till in the 2010's and it held up pretty well then.

It's got some pretty compelling story arcs and character development that hold up well. And the campiness is leaned into enough that it feels good as part of the show. There's some filler episodes but that's kind of expected with a show with that much run time(the concept of shorter seasons that just focused on the story arc was still pretty foreign)

It definitely went beyond just kill random villain of the week and had some themes that are still relevant today and it dealt with them pretty well for a show ostensibly aimed at teenagers.