Surely on that argument, the body of almost any animal that is bigger than us is actually a more complex piece of machinery. Blue whales are massive, for instance and are made of far more cells than we are.
Well, not necessarily. The key factors are heterogeneity and complexity rather than size.
E.g., the difference between a stick of RAM (relatively homogeneous and simple) vs a CPU (highly diverse).
In fact, when it comes to brains, larger cetaceans seem to have simpler structures when compared to human brains, even though they're larger in absolute terms.
