Keep Topic name same as Category Name
In that TOPIC Add a TAG with same Name as Category Name.
Easy to remember that at least. Then comes the case of modifying category template to filter data by the Tag Name ... Works fine no matter whether it is a small site or a site as busy as CNN/NY times and resolves your difficulty about remembering TAG Names.
Adding another overhead for anything which can be achieved right now isn't the right path as then busy websites will then complain that VIVVO is bringing the server to it's knees