QR was the first airline to use the Super Diamond seat (as on the VA 777), there was another reverse herringbone before it called Cirrus that was introduced on US Airways and versions of it became the CX business class seat.

The QR version on the of the super diamond seat is installed at a 24 degree angle and a higher pitch, the manufacturer then created a more dense version installed at a higher angle from the aircraft centreline and a few inches less pitch to be able to fit more seats in the same space and that is when the seat became popular with other airlines. The higher angle makes the footwell slightly wider and shallower in depth but makes the bed shorter and overall space in the seat smaller, VA was an early customer.

As the seat evolved to its latest iteration such as on Starlux, with improved materials and engineering they were able to carve out more space including in the footwell with the smaller footprint. I would imagine a seat combining the lower density layout on the QR version with the latest improvements would be amazing.

You can see the difference in densities with how many of the older Super Diamond seats QR has between doors 1 and 2 on the A350-900 compared with some other airlines on the same type with similar LAV/Galley configurations. The QR 787-9 goes back towards having more industry standard seat footprints in J.