Hey there!
Just to tack on to @owidjaja's post, you should be able to be nuanced ie. provide a view that is a little more sophisticated. You can also go off topic, provided you link back to the question and make sure it fits into your argument. In your example, provided you show evidence of how Stalin's flawed leadership affected the economic state of Soviet Russia at the cost of human resources you can factor that in. In my opinion you could probably write something along the lines of 'the social cost of economic progression in Soviet Russia was undoubtedly great, but likewise the leapfrogging of multiple nations in the economic sector cannot be ignored.' or something like 'it can be argued that the social cost of large-scale economic boosts was worth any social cost to advance backward Russia.' Basically back this up with stats (really important, there are plenty of stats which show how big the change economically was [use your industrialisation and collectivisation notes and stats, perhaps even purges and gulag stats as required]), because given you can back something up you can say whatever you want (also given that it's cohesively structured and well argued of course
). So basically echoing the above post (fence sitting thesis is totally okay, but have a strong judgement, that'll be your 'sophisticated thesis' so to speak.) As for body paragraph ideas, probably look at social, economic factors of economic gain ie. five year plans, collectivisation, gulag, censorship, increased government control, establishment of rigid political structure etc. Could even look into purges (at a stretch).
Hope this helps!