The notion that Stalin didn't want Roosevelt and Churchill to treat his soldiers as expendable made me smile. If so, it would have been because he didn't want competition.
Roosevelt and Churchill would have been in line well behind Stalin and his generals in that regard.
A Soviet soldier was a cog in a machine and totally expendable in the service of the socialist state, which was demonstrated most recently by the purges of the late '30s. That's why their morale was so high early in the war.