I don't want to make this longer than needed; I don't know anything about die Linke and MLPD to speak about those. I would disagree about the relationship between the USSR and the Warsaw Pact countries, since while they definitely had some autonomy, in any case where they were against the USSR interests their leaders were promptly changed. What I find most unclear is your third point. I already noted they lasted for really short periods, and I agree, the FTU was an anarchist state (Republican Spain, with the CNT-FAI can be considered an in-between). Why did they, however, show not to be a relevant model to run a country? The fact that both were grassroots based, and democratically organized would make me think the opposite. Is it because they weren't able to defend themselves?