Yes, I've read alot on the Soviet Union, Communism, and Socialism. The ideologies and movements really fascinate me.
By changing the system, I suppose you mean revolution? Certainly the political and economic climate is appropriate for such a move to take place, although I don't see the Communist and Socialist parties having the vigor that they once had. So it is fairly unlikely that any revolutions will take place, at least in the United States or Europe.
The USSR itself was never meant to exist for all the time that it did. The October Revolution was meant to spark a worldwide revolution, and not necessarily a specific Russian one. When worldwide revolution failed, it threw Marxists completely off guard, who believed that the climate was proper for such a thing, they made due with what they had accomplished.
Communism itself, as you stated, is not at all an "evil" system like so many people have been programmed into thinking. But, like Christianity, people have done things in the name of Communism which have muddied the name.
I guess that the thing is, in prosperous times, people tend to stray away from Communism as a result of their own greed. But, as this economic situations spirals ever downwards, perhaps they'll gather momentum, as they did during the 1930s? I mean, the Communist Party in Weimar Germany was, in the last "free" electrion, the largest party behind the Nazis. Had the original Spartacist revolution not been so brutally crushed by the Freikorps, it's entirely likely things would have panned out even more differently.
As you say, the context of these groups will always be tainted by the likes of Stalin, same with Christianity and Islam being tainted by extremists and fundamentalists - if you strip away all of the fringes and just look at the main ideologies, they solve many of the problems.
Back to classes, one can clearly survive. If the Anarcho-Communist system is put into practise, one eliminates the need for an "upper" or "lower" class by ensuring that all jobs are equally rewarding to all others. Regardless of Marx's slightly over-hopeful outlook on humanity, this system can be employed with a greater vigour due to the fact that you have no ruling elite, as were so bitterly despised during the Soviet Era. People looked upon the likes of Stalin (who, as you said, was denounced by the two true founders of the Communist Party in Russia) as the "Ruling Class" which totally shattered the principle of the movement he claimed to be leading. In the truest communist society, people work only for one another and you don't need a government - people rely on their own morals to sort problems.
Of course, it is easy to pick and flaw at this idea. People will just run amok, killing and stealing left right and centre. But, one could perhaps envisige that, without the class system, there will be no wealth/social divide which is, of course, the main motivation behind the majority of killings and robberies. If no-one has a bigger living space than anyone else, and people all have equal access to whichever resources they require, there is no need to steal, surely?
I don't know... I mean, sometimes, I feel optimistic. I want to believe that there are enough people out there against this current opressive class system to put this sort of plan into action. Yet, on other occasions, I feel so helpless when I see newstories of Footballers complaining that a wage of "£150,000" (about $220,000) per week is not sufficient. I just baffle at the thought... Maybe the class system has become so utterly rooted into our conscious in Western Society that it would take more than a miracle to finally destroy it?