Hello. Here, "what is" is used correctly. However, I would suggest a different change to the sentence. In this sentence we have two metaphors. "The commanding heights" suggests a mountain peak. However, "to heel" suggests controlling a dog. When the two phrases are used together, we picture a mountain on a dog leash. The pictures created in the mind do not go together. An alternative might read, "Bringing the snarling power of the modern economy to heel might be expected from what is, after all, a communist regime."