I think everyone who works with Adobe Analytics has run into a situation where we would like to combine the value of two or more dimensions into one value for reporting. If you have an eVar for City and a prop for Country, it would be awesome to be able to combine both to a value like "City in Country", just like a Calculated Metric. If it only works for dimensions on the same hit we would already have a lot of value.
Today, I solve this by tracking the value in a combined way and utilize Classification Rules to separate them afterwards. This works for new implementation but does not help for historical data or new use cases.