As an addition to today's support for prompts in data connections this feature would add the ability to define a static limit to data in a data connection. This could for example be done by specifying unique values from a column or by writing a custom expression.
No time to waste on this one if Spotfire should use data connections more. Then limiting your data should be enabled in as many ways as possible to protect the databases you connect to.
Have a look at what MS Power BI does for free. Smart filters based on data type so that DATE can be range constrained etc.
Customers keep asking for the need to have OOB time related query filters like 'Today', 'Last 7 days', 'Last Month' and not need for a custom query.