At the moment we have a very nice collection of different ways to query for human tasks, including:
work item ids
process instance ids
(actual) task owners
However, while some combinations of these queries are available (getTasksOwnedByStatus, for example), there are a number of combinations that are not available. Doing these combinations (business administrator and work item id) means filtering the result of disparate commands (at the software level) which involves multiple retrievals from the database – as opposed to a combined query which would minimize the slowest step (transfer over the network/line).
So this issue is for a Task(Query)Service method that allows all of the above as a parameter and (dynamically) produces and uses a query based on the input in order to efficiently query the database.