On the economy, I recommend Farm to Factory by Robert Allen and Rise and Fall of the Soviet Economy by Philip Hanson.I see. I'd be interested in investigating this further too, so I'd like to ask you for citations here too.
Rise and Fall of the Soviet Economy has a good section on the political changes in the period. Otherwise, my sources have been papers on Soviet political history, and I have a terrible memory for those... (I have alot of academic papers by various professional Sovietologists of various, and they can blur into each other.)So liberalism developed later on, but what specifically led to that? I'd be interested in investigating that further, so if you would cite sources in your reply that would be appreciated.
A planned economy can only be as good as the plan, and the Soviets had a good deal of room to improve their planning. Note that there are no alternatives that fix everything forever - any functioning economy or political system needs to be in a constant state of re-inventing itself to remain healthy. But there is a path for the Soviets to basically implement their good ideas in the 80s and continue long enough that they have the time and resources to have a fighting chance at implementing the changes that would meet the challenges of the 90s, the challenges of the 00s and so on...I would be interested in hearing more about those alternatives!