We've seen that different teams use the explode by wiki feature differently. Some, need the all value, some don't, and some can not afford having a full list of all wikis, because their queries take too long to be executed 800+ times per day, and instead use a subset of them. I think it's better to make the feature more generic and let the teams specify their own lists as opposed to have different lists and parametrize each one of them. Also, we've seen teams repeating a considerably large list of values to explode in each one of the reports. This feature would also reduce that code to something more maintainable.
Example:
reports:
some_report:
granularity: days
starts: 2016-01-01
explode_by:
wiki: list_of_wikis.txtMaybe reportupdater could assume that a value list with a single value means a file path.