So, this is a question asked often enough - Dr. Doom - honorable villain, or bastard who will do what he wants and then justifies it as honorable after the fact? There are writers for both sides of the arguement (John Byrne and Chris Claremont, for "Doom is ultimately honorable and actually quite noble in his way." to Mark Waid for "Doom is a liar and a cheat who pretends he is honorable when in fact he's a total fraud"), and both sides are valid. In my opinion, this is a question of nuance and subtlety - which really shouldn't be a surprise given Doom is, even more than a scientist or wizard, a politican and diplomat.
Does Doom have a code of honor? Yes, but it is a twisted one (and even Byrne acknowledged this). A true diplomat, Doom's one to parse his words, his thoughts, even his perceptions, to maintain this code to himself. Keep in mind, the end result of any action doom undertakes should be in the service of Doom. But they must also bring Doom glory within the wider world. One thing Mark Waid did get right is Doom's need for external validation - it's not enough for Doom to kill Reed - he has to bring him down so that the world can see that Doom was always better than Richards. He doesn't just want to conquer the world - he wants the world to acknowledge that it needs him to conquer it.
Once you remove the external audience (i.e. the world stage, and especially the people of Latveria - more on that later), Doom becomes much more dangerous and deceitful - because he's less likely to gain any kind of external validation, he's more likely to betray, to go back on his word, to find a loophole (which he's usually smart enough to build for himself into any agreement). Like any politician, Doom's dealings behind closed doors are always darker and more devious than when he's in the public eye.
Latveria is the key - Doom has a captive audience who hangs on his every word, and it is there that he MUST be honorable and noble and all the things that he needs to convince himself that he actually is. So his actions there, and on behalf of the citizenry (his underlings are another matter - they know what the score is because Doom demands they be competent enough to carry out what he needs them to - so ultimately they respect him, they fear him, but they know what he is. Which is why he kills them if they step out of line). The misstep Waid made (and it was immediately reversed) was taking away Latveria from Doom. Without a nation that loves him, that feeds his need for validation, Doom becomes more dangerous, not less so. Resources don't matter when you're as dangerous as he is.