Here's one.
http://www.amazon.com/The-Impossibl...54566389&sr=8-1&keywords=the+impossible+state
It's a fair statement that during the Cold War, NK was doing OK. It had a manufacturing base, hadn't wrecked its agriculture and had two supportive trading partners in the USSR and China.
When the country was originally divided, the North (which had most of the industry, thanks to Japan) was richer than the South (which was mostly agricultural).
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The statement that "NK was doing OK" "during the Cold War" can at most be true for the early Cold War, if at all. North Korea had to re-negotiate its debts in 1979 and defaulted on its loans (except those from Japan) in 1980. And it does not look very plausible that a country does OK for several decades and then suffers from a famine with several hundreds of thousands, possibly millions of deaths. There must have been deep seated problems preceding this crisis which made it have such catastrophic effects.
To answer the original poster's question: One of the pillar's of Kim Il Sung's ideology of
Juche (to the best of my limited knowledge this means something like 'national autonomy') was economic autarky. If a country has to achieve autarky or something near it, its economic possibilities become much more limited than that of a country that trades more freely with the outside world. This is true no matter whether autarky is a self-imposed goal of the political leadership, or whether an embargo or blockade from other countries forces the country to become autarkic. And it seems to be true of both socialist and market economy countries.
So if Kim Il Sung recognizes that a policy of autarky empoverishes the country, one very big problem could be removed. Perhaps it would have been best, if he had recognized that autarky in a country that small was illusionary anyway, and had not even tried to achieve it. Of course it would have been better still if the regime in North Korea was not socialist at all, but a POD removing the socialism would probably also remove North Korea's existence as a separate country.
I have read one text which said that at least at times the concept of 'interest' was not taken into account in North Korea's economic planning, "because it was a capitalist concept". Perhaps North Korea's economic planning could be made more realistic if interest and other 'capitalist' elements were integrated, that were ignored at least at times in OTL.
Allowing private small farms and private small businesses and giving state factory managers some autonomy in their decisions. It seems at if small illegal, but tolerated, private farms and businesses keep the country from starving at present.
And, as has already been stated, reduce expenditures for the armed forces drastically.