The problem in the 90's was it happened too late and happened a little too quick. The big monopolies needed to be broken up. Each building should initially be its own enterprise. The enterprises consisting of less than 25 workers simply should be partnerships with ownership split equally among them. Larger firms issue stock with 5 grades A,B,C,D,and E distributed equally among workers. No stock can be sold until the end of the first year with various public education programs to show how stock works. At the end of the year grade A stock can be sold, at the end of the second B stock can be sold, C after the third and so on. The initial stock price is at book value.
As far as during the Cold War period itself I think at the very least it needs to dump the Five Year Plans and adopt
Market Socialism. Not having real prices really hurts you. The earlier this happens the better.