Improve parameter passing in SSRS

Parameters are the key to building interactive reporting solutions but complex report designs can become difficult to maintain. Let's say that I have ten items on a dashboard style report that pass all the parameters back to the same report (which is necessary to maintain the state of previously-selected parameter values)... Now I add one more parameter to the report and I have to find every item with an action to add that parameter. If there were some kind of a parameter collection object, similar to the property bag in old VB or the Request/Response/Application/Cookies objects commonly used in ASP.NET; this could be used to add the new parameter to the collection and simply pass the whole thing as an object to maintain the state of previously selected values. I have several specific thoughts and examples to share on this subject.