Why is the process model that I generated from some object life cycles so complex?
One possible reason that a complex process model is generated is that the original object life cycle(s) contain many self-transitions. If this is the case, try removing those self-transitions from the object life cycle(s) and regenerating the process model. Generation from several object life cycles with few synchronizing activities might also produce a complex process model. Try to identify any missing synchronizing activities and regenerate the process model.