I happen to come from the former USSR. Putin is a standard kegebun - i.e. a being on whose behavior the only restraints are the external circumstances of superior power. If needed, and when needed, he could out-do stalin without batting an eyelid. If there has been no such need perceived by him up to the present, it is not yet reason enough to give him credit for.
are you old enough to remember stalin's reign, particularly before the great patriotic war?
The purges (both military and civilian) were something on a scale which had not been seen in the industrialized world at that time before though germany was only a few years behind on the scale of murder. Stalin apparently had people killed for the most bizarre or misplaced of reasons, and also managed to kill almost any officer with any initiative and talent or prominence. It is nothing short of a miracle that Zhukov survived the purges to even fight the japanese in the western part of the war.