Lenin thought he was Lenin, too, or that he was the revolutionary capable. Perhaps that's not actually an impediment but a prerequisite?
No, Lenin specifically did not think he "was Lenin." By all accounts Lenin was a very unassuming and modest man, unconcerned with his image or his posterity. Lenin was exactly the sort of person a communist should be: someone who does their small part in the global proletarian struggle throughout history. Lenin didn't set out to change the world, he just took what came at him using the gifts that he had, and that happened to land him in a position of leadership.
Or in other words, Lenin was not thinking "I am the one who has to do this." When I say that everyone today thinks they are Lenin, it's because they all imagine themselves to be great leaders of unquestionable correctness, and if, like Lenin, they just wait it out, everyone will one day come around to seeing that they are right and their specific tendency will prevail above all others. There's no room for compromise or other opinions, and everyone must be the great leader.
The point isn't not to admire Lenin, or even look to him for an example when appropriate. The point is, though, that each person should just do what they can and not worry about power or fame, or even if their own specific theory is right or not, and just worry about what little things they can do to help educate, agitate, and organize the working class into defending their class interests, thinking collectively, and acting politically based on those two things. The leaders will rise to the top, and it will be the ones we deserve, not the ones who seek it. These emulators of Lenin make the same mistake of the Marxist-Leninist romantics: they imagine that all of history is an inevitability which need merely be emulated in order to be recreated, which is desirable because everything was perfect. The concepts of circumstance, of luck, of improvisation, these are alien to such people. The point isn't to emulate Lenin, the point is to understand what made Lenin be Lenin and not someone else. How he thought, why he chose one action over another, how he addressed certain situations and why. And finally, to understand that Lenin did what he was able to do because of circumstance. You can't transpose him onto any other situation and expect the same results. Put him in the USA today, and he would likely be near-useless, or at the most, nothing more than your average Party member.
I find it very telling that the final two chapters of
To The Finland Station are called "Trotsky Identifies History with Himself" and "Lenin Identifies Himself with History." A perfect summary of the attitudes of these two men.
I find your answer that they were simply emblematic of the culture of their time and place compelling to suggest that they weren't any less suited necessarily than anyone else, but I don't see how it precludes or crowds out the possibility that because the revolution did happen to come from military leaders it was therefore biased towards oppression. (Or at least more oppression, enough or not to pass any tipping points, for that any specific case of revolution). But thank you for your knowledge.
I don't think any group from that era, even the liberal democratic parties, could have maintained a significantly less oppressive regime during that time. Not because "durr Russians are barbarians" but because of the very severe threats to any established government by other groups who resented that establishment. Communist power came first to Russia because of its unique mix of powerful class interests which collided there: both feudal as well as capitalist class struggles were at work simultaneously. This is why the emblem of the Communist Party there was a hammer and sickle: the party represented the alliance of the
workers and peasants against all oppressors: capitalists, barons, and tsars. The same social weakness which allowed Bolshevik power in the first place was also the weakness that any subsequent government would have to face and rectify.
I suppose but that's a different topic.

My interest is more about those whose success as revolutionaries was judged as a part of their success with violence, and implicitly since violence is the ultimate oppression, be ill-suited for leading liberation, and if Cheezy had explored that in his studies.
Violence is necessary when facing a violent system. Pacifism may sound warm and morally upright, but it only works if your enemy has a conscience.
As I said, by the time Luxemburg died I had no complaints about Bolshevik behavior. Violence was used judiciously, where and when it became appropriate, and never before, but it
was used. And I'm okay with that, because allowing the anti-capitalist revolution to fail where one could have prevented that outcome is a worse crime, in my opinion. It is not one arrived at without significant contemplation.
What people thought they needed to do to make the best of many goals of fighting Kaisers, Nazis, Tsars, etc while also building a modern industrial state, a foundation for current and future emancipation, etc. was what they thought they needed to do. Obviously some things those specific folk did worked out (fighting off Hitler) and other things didn't (communism).
So it's not a smug judgment from across time, it's a question about the nature of circumstances and the people in them.
I don't see it as a statement about anything but history itself. They tried and failed, as you said, because of historical circumstances. I would say view it as an experiment, but that would ignore the fact that each historical situation is unique, as will future ones be. You cannot look at an individual, or even a group of examples, and say that this is conclusive proof that something does or does not work, because there are infinite variables in each situation as to make them unreproducible. That is why Marxism ejected utopianism in favor of a coherent and systematic
theory: a social science. It allows us to understand things on a theoretical level and reapply lessons to understand new circumstances as well as old ones.