Well, for one you can take Stalin out of the picture in late twenties, as it would give his opponents a free hand(or at least not a bullet in the skull) in soviet government, which wouldn't avert forced collectivization per se, but it would mean that much less forceful and more voluntary approach would be made. Thus, it should eliminate the cause of 1931-1933 hunger, and would mean that about 8 million citizens would be alive. Not to mention their children later on, as demographic transition was in full swing.
The absence of paranoiac the level of Stalin at the head of the government would most probably mean no 1937 purges, which, depending on your believe in competence of Soviet RCW and post-RCW military stuff, would rather mean that even if soviet industrial power base would be less then with alive Stalin(which is not a given), not so much of equipment would be lost in the early days of Barbarossa.
Also, I'd think that without a Tsar-like/Furher/whatever-you-call-it totalitarian leader figure which alone makes all decisions, the soviet leadership would probably be less inclined to play Hitler's game, which throws another miliion of butterflies. Not to mention the loose probability of Hitler at all.