Yes and no.
I agree that a better political system would do wonders, however this is a wargame and not political simulator 1940. The things you suggest might be more realistic but they won't necessarily make a better game. Also, it'd be incredibly complex to make it work and then to balance it. It's not just politics from a government point of view, you'd have to incorporate influence people have on said politics. So you'd have to simulate popularity of parties that stems from socio-economic troubles/fortunes. Why did Hitler rise? because the social economic trouble in Germany at the time. People were pretty poor, food was expensive etc. He promised them something better. He just won from the commies who tried the same. You'd need to simulate the causes of these hardships and the way people pick their leaders and also how leaders react to all this. Why was the US isolationists? Why didn't the Dutch prepare for war? Why didn't the Allies try harder to stop Hitler? Then there's the way governments work, there's democracies, dictatorships or autocracies.
Then there's the little aspect that politics play little to no role after the war has truely started. It only affects the buildup.
That's all way too complex to incorporate in a game that spans 10 years. Let alone to actually make it all work.
I do think there's room for improvement though. But I still say it shouldn't be a priority. And I would prefer a relative simplified system that's still fun to use and you'll have the same effects.
I think PDX has chosen the right path to remove stockpiles etc. so you don't get to use your hindsight. Because as you said, politically stockpiles need to be justified. It's all intertwined and the focus should be on army building and fighting the war, trying different strategies for how to win said war. Use more or better planes, go all tanks, navy etc. etc.
It's interesting to explore other ways of starting the war, but do we really need complicated political systems for that? No we don't, better not to, because a realistic sytem would block a lot of the alternatives.
Back to stockpiles, I agree with
@safe-keeper . And I reïterate that there is definitely room for improvement and expansion of the trade/political-system, but right now I'd prefer expanded/imporved Air- and Navalcombat methods.