First of all, thank you for a sensible and pleasant reply. It really is a breath of fresh air in here :)

I think the small markets only go so far. Many things in a modern economy don't work well on a small scale. This is actually where many of the worst examples of capitalism come from too. With high barriers to entry into areas like mobile phones, medicine, social networks, utilities etc. some companies become near monopolies. But as you say, various solutions could be tried.

Another issue I can see is the difficulty of ensuring power is not too concentrated in a small group of people. But again, various things could be tried and capitalism has these issues to a lesser extent as well.

That is, if we have more than one try... The thing that concerns me most is how to try them out without driving the economy off a cliff and without violence. If we could try these systems on a smaller scale next to capitalism, than I am all for it, lets experiment. But most people here talk about a revolution or confiscating all wealth above a threshold (dismantling the capitalist system). If this is really the only way to try communism, then I think it is much more sensible to work on gradually improving capitalism instead. There are capitalist countries that are very nice to live in (like the Nordics, Switzerland, Netherlands, ...). So we know this is possible and even more or less how to get there.