Currently in workflows, you only can Create/Update an Opportunity (this assumes whether you choose duplicate or not). However, if you have multiple Opportunities in different pipelines, there is no way to update it unless an event is triggred by the Opportunity. For example, if I have 2 opportunities in 2 different pipelines, and I trigger a Contact Update, but I only want to update one of the Opportunities, I cannot do that. We should be able to navigate from the contact down to the specific Opportunity to manipulate.