Stalin was the worst, most horificly evil leader in history! But his defence of the soviet union in the "great patriotic war" was satisfactory if not effective. It was the bravery of the soviet people that won WWII, though it cost them dearly.
Professor I. A. Kuganov estimates that some 66,000,000 people were killed in the USSR between 1917 and 1953... (This does not) include the 30,000,000 killed in the second world war.. To put this in context the russian federation now has a populattion of 150,000,000 assuming the ravages of communism had never occured the actual population should be about 300,000,000... Robert Harris - Archangel p156
It is safe to say that even if Trotsky could be "a bit cold" or "ruthless" it still would not have amounted to 50% of the population killed for his own glory/peace of mind. Even if trotsky had not been able to modernise the USSR as fast as Stalin he would have had other advantages.
His stance on the spread of international Socialism through revolution would have had a direct effect on the out come of the spanish civil war- Stalin stole the republics gold, took over the military and wasted the lives of the brave spaniards in useless "prestige" operations to show "the profesionalism" of the Soviet Army; His performance did much to raise his reputation with the conservative governments of britain and france, as well as dispell thier fears over the export of Soviet revolution to thier own countries- but it also lost spain to facsism (and through out europe weakend the socialist cause; the only real oposition to the facists), The repubic started the war in a good position, though they were isolated and hated by the rest of europe, britain and france (under presure from british threats "to leave them at the mercy of the axis powers if they didn't do what they were told") organised strong non-interventionist organisation against the republic, while allowing the germans and italians a free hand in arming the Nationalists.
The repuplic, givern suficient aid from moscow and better strategies, could have won the civil war or at least have continued resistance untill war broke out in europe. A victorious repubilcian spain would have been a major victory also for Trotsky and international socialism- though it could easily have turned the british and french against him.
I would like to think that if britian or france had tried to enter the war on the side of the Axis (as oponents of international socailism) it would have meant civil war in one or both those countries, Apeasement was one thing, but alliance with the nazis? I don't think any one would have stood for it.
Imagine the start of WWII in 1938 (the invasion of czechezlovakia would be resisted with aid from russia, and the czechs were actualy in quite a good position to defend against the germans, thier defences in the sudetenland were very formidable) spain is either all republican with some right wing partisans causing trouble, or at least half and half, France is almost certianly in civil war (the country was very unstable at this time, tensions between left and right were strianed to breaking point, it was only the threat of the germans that bought both side together- though it was still an unhappy marige, the communist sabotaged the planes and tanks that were used in the defence of the country because they didn't want to go to war- the Communist propoganda of the time was aimed at non agression). And Britain? The UK would never have been in a position to do anthing apart from defend itself right up to the mid 1940s, the battle of britain could only have been won with help from the americans, who would never have been in favour of aliance with the nazis (whatever you can say about the USA you have to agree that Rosevelt was a good man).
Trotskies Russia would have been hard pressed to defend against the Germans, he didn't foster the same kind of Virulent nationalism favoured by Stalin, but not entering in to the non agression pact would have alowed the rusians to sut up thier traditional "defence in depth" which also would not have been weakend by thier over extention in to Poland (a large area of undefendable land).
Perhaps trotsky would have failed in the defence of Russia, but if he didn't you can bet that the fate of the defeated German people would not have been as bad as it was under Stalin, and that a russia with 100% higher population would have been beter suited to a communist economy.
Maybe if Trotsky won that battle against Stalin there would be a thread like "if stalin could resist Trotsky what would russia look like" or something of the kind.
