We often have a large number of deals under individual contacts and organisations.
Currently, the contact and organisation pages only show up to five open deals in the side panel. If the open deal you want to click through to isn't one of the five displayed, you have to select "All Deals", which then brings up a list of all open and closed deals - often a very long list.
There needs to be another button to select "All Open Deals", as well as the option to filter the results by pipeline and stage etc. so that you can quickly find the deal you want to drill through to.