I dunno it it would add flexibility, you'd be stuck with that index number no matter what dwg the part showed up in, leading to possibly having 2 different parts with the same index #. To me, fixing the indexes per each repeat region BOM allows more flexibility. Or, at least the flexibility I find more useful. Me, I just lock the indexes of the entire region at once and move on. Flexible parts USED to wreak havoc in BOMS, requiring me to lock each index individually, THEN lock the entire region to get them to stay the same index #. Doing either or didn't work for some weird reason. I had to do both.
We don't publish BOMs (with part numbers) on drawings, we only item number (bubble number). Our BOMs contain item number, part number, and also sequence numbers. Our assemblers don't like that we don't publish BOMs with part numbers on our drawings. So what they have to do is match the item number on a print to the item number in the MRP. This definitely has it's pros and cons. Unfortunately, I can't change the process.
That being said, we can still "put" a BOM on the drawing but it would be placed outside of the drawing template and not be printed as a contained item. This BOM could be used to bubble quickly because you can bubble by parts in a view. As mentioned, if this table had all the normal index/part number stuff from the model tree but also a bubble number column that can be quickly edited as a text item and be associated/linked this would be a little easier to manage. If we have to change bubble numbers in the future this would be arguably harder to screw up by some other engineer that's never messed with repeat regions.
Anyway, repeat region - select - select - unfix - fix - edit - whatever - whatever, does work.