Spicy question maybe, but I'm interested in your takes.
Personally, I think there's some major issues with at least the terminology of the 2 phase model of lower/higher stage communism or socialism/communism as the terms are used in classical theory. Specifically the 'lower stage' or 'socialism' term is problematic.
In the age of revision and after the success of counterrevolution it has become clear that there is in fact a transitional phase leading up to the classical transitional phase. Societies did not jump from developed capitalism to socialism immediately and even the states that arguably did were forced to roll back some of the core tenets of 'socialism' as it is described in Marx, Engels and Lenin. Namely no private ownership of the means of production and no exploitation of man by man.
To ultras this just means countries following this path aren't socialist. So then China isn't, Cuba isn't, no country still is really and those of us claiming they are then have to be revisionists. And to be fair, if you're dogmatic you can make that point going from the source material. China itself recognizes this inconsistency, thus not seeing itself at the stage of socialism. Yet it's a socialist state. But then what do we actually mean by 'socialism' when we use the term like this? Just a dictatorship of the proletariat? Any country in the process of building socialism?
That question comes up all the time and confuses the fuck out of people, because the term is either not applied consistently or as it's defined is lacking. I think discourse in the communist movement and about AES would profit immensely if we had a more consistent definition or usage of the term or a better defined concept of what that transition to socialism is and how we should call it.
I always felt as much as ML and other adjacent ideologies maintain that they are materialist, in effect they don't act as such. This is partly informed by my experience online and in in-person organizing.
There's a significant ignorance of the physical and natural sciences which do well to inform a materialist perspective. When I have brought up points from Biology, Physics, or some things which are more contemporary like Psychology (and the effectiveness of therapy) I have largely been brushed aside. I have some education in these areas, and I feel that many of the MLers I interact with have very little. Dialogue becomes nearly impossible as I am hitting heads against ideology as opposed to empirical evidence. This may be due to my background in the sciences as compared to the many individuals I interact with in-person (I don't know about online) having humanities and arts backgrounds. Of course when I was in the space where the people who were well versed in the sciences or engineering were around, I'd hear similar ridicule against people who were less technical.
My hope would be at least among MLers that there would be space for critical thought and discussion but that has not been the case. In fact technical people who have a less coherent understanding or ideology, more or less piecemeal, at the very least seem more amenable to discussion relating to non-human materialist phenomena. Though there is often moral bankruptcy involved as well unfortunately.