To the last question: workers didnt own means of production, they nominally controlled the state which controled means of production. (this is trot argument->). Because the control of the state was sliding toward the party, which slowly became class in itself, the ownership of means of production was not in the hands of the workers. Here lies one of the trot/pro-stalin thingies - trotsky thought it was obvious it would happen and even that it already did under stalin, pro-stalin viewpoint is that it didnt under stalin, but happened during kruschev.

I personally think trotsky suffered from far-sightedness, could see clearly where it was going, but couldn't get over his hatred of stalin (some deserved some not so)