Marxist-Leninists are by far the most common type of Leftist globally, so pretending that they are just a small niche is very western-centric.
Considering this is a western-oriented service, and I live in the west and largely interact with other people in the west, it seems to me that it makes sense to mostly consider the political makeup of the west. I don't see the point of collaborating with people on the other side of the planet when it comes to local politics.
Regardless, do you have any sort of citation regarding the prevalence of certain political ideologies? I can barely find national sources that divvy up ideologies enough, let alone worldwide. And then I mean an actual survey regarding ideology, not membership of a party or voting records. Plenty of leftwingers are members of the democrat party for example, but I wouldn't consider them to be neoliberal or something. Genuinely curious about this.
As for fascism, you argued that the Soviets should have allowed more opposition. In the USSR, that opposition consisted of Tsarists, fascists, and liberals, all of which ultimately were responsible for killing millions of citizens of the USSR.
I didn't argue anything about what the Soviets should or shouldn't have done. The USSR banned far more opposition than just those groups. And it's not like the Soviets themselves haven't caused millions of deaths themselves.
As for how the USSR was run, this is just generally false. The Soviet method of democracy was in place, and the economy was run and planned by many, many, many people.
The direction of planning was centralised into the hands of very, very few people, even if the details were worked out by more people. But I don't think anyone can argue that Stalin wasn't a dictator, or that Kruschev eliminated anyone who could oppose his rise to power, etc...
As for centralization, you agree with Marx about it centralizing. However, rather than move forward in time, you try to turn the clock backwards. If centralization is a given, then it should be democratized across the whole of society so that we may continue to increase efficiency in production and work fewer and fewer hours to cover more and more needs and wants.
I don't try to turn the clock backwards. I want to avoid the consolidation of power and wealth in the first place, which is what historically has always led to mismanagement, corruption, suppression and in worst cases wars and genocides. Rather trying to redirect that accumulation of power to a small group that has to somehow democratize it, said power should immediately be spread out over many groups or individuals. Easiest example would be wealth accumulation: strong progressive taxation with a rate of up to 100% at the maximum acceptable level of wealth. That money should immediately be distributed to the rest of the population, without intervention from a government who could redirect it for other purposes. I don't advocate for the abolition of capital or property, because I don't expect humans to be selfless enough to do so. But at some point when someone has 'enough', then that should be that and they shouldn't be able to obtain more.
In your original comment, you expressed equal distaste for Communists and Nazis. Communists have historically had far fewer skulls under their name than liberal regimes or fascist regimes.
I don't care. As I said I don't care about counting skulls, I care that the pile is considerably large. I don't care about which method was used to count the exact total, whether that's per capita, per year, per war or whatever, as proponents of both capitalism and communism keep doing to lower their own totals. I don't start liking communists because the Nazis/capitalists/feudalists/whatever were worse. They too have blood on their hands and that makes me dislike them, it doesn't get more complicated than that, and no amount of apologizing for these deaths will suddenly make me think otherwise.
Either way, though, what's your alternative that causes you to break from Marxism? Where is the evidence of its success, and your plan to get there? Genuinely, I am asking honestly.
Best place to live in the world right now is likely the Nordics. Ultimately capitalist, sure, but with strong social mechanisms so that nobody ends up falling behind. Social democrats have a fairly good track record of not ending up involved in genocides and life seems to on average improve the most with social democratic policies. I live in the Netherlands, which is a bit too much on the right wing-liberal side of things but I do very much appreciate the electoral system, with proportional representation. It creates a lot of parties, sure, but that spreads out power and that prevents radicals from suddenly seizing power (as demonstrated by the current government that consists of a radical party that isn't getting any radical policies through + 3 more moderate parties trying (and succeeding) to keep everything in check). We also do have very rich people, but there aren't a handful of them that dictate all politics for example. The judicial branch manages itself and is properly independent, which keeps the executive in check.
It's a stable government form, that can incrementally improve things without letting people fall behind.
Complete sidenote: countries in general should be smaller imo, protected by defensive pacts. That would reduce imperialist tendencies from now large countries like the US, Russia and China (again by limiting the accumulation of power).