At the moment, if you want to see how many oppprtunities you have for a contact, you need walk through text base views of status and stage - not intuitive and very confusing. If you want to check for duplicate opps then good luck finding them!

However, the one advanced filter that is missing is View by contact. In the pipeline kanban view see a graphic of all the opps for that contact, visually showing what stage each opp is at. Look up Flowlu - it does this VERY well.