Will a first row hint do any good in BOXI? It appears that the report does not render until all of the rows are returned by the query, which would mean first rows is pretty much useless in a BOXI report.
In my opinion, the FIRST_ROWS hint is useless in BO because of the reason that you mentioned.
In BO, a query should be optimized for the best throughput rather than for the best response time. And this is even more important in cases where a lots of rows are fetched from a database.
ALL_ROWS might be a place to start…but experiment, there are loads of the damn of things and you can combine multiple ones together. Its kind of like hard coding though, not something you want in a lot of reports. Plus over time as the profile of your database changes the execution plan potentially changes…then a really useful hint can suddenly be a source of pain…