I sometimes like to add "obstacle" balls to the table (2 or 3) to have extra traffic for learning position routes. Pros could add the 6 extras, break the full rack, spot any extras made, and play 9 ball from there! Complicates the break and the runout... might be a fun train wreck to watch!
As for the original idea, it would be interesting for sure!
This is what I was originally thinking would be a good practice tool to place the extra balls out there just as blockers. I would place them on the table and then break up the rack and see what clusters are there.