Whatever I consume affects me, but as a citizen and as a worker my behavior affects those around me as well. We need to preserve individual rights while allowing collective assessment. The idea that too little attention will be given the most important matters in a participatory economy is ironic coming from advocates of economies where almost no time goes to the most important matters, at least the most important matters to the well being of nonelite citizens. And, anyhow, how much energy goes into assessing one collective project or another, one bit of research or another, is, in participatory economics, a function of the extent of public concern and controversy about the issues themselves. And central planners obstruct participation.
Central planning isolates people from one another and propels elite rule.
No, with networks of consumer councils. To me you are arguing over trivia. But I just can't see how people will function as you describe. You can't grab all that you might want. Remember specific choices are anonymous, but quantity isn't.