I haven’t given this a try yet but it will definitely change the dynamic of how things play out. I might also steal the “exploding dice” mechanic from Spartan Games so Rooks could have a chance to Assault.
Or adopt the officer method from KR 16?
If a squad has an officer commanding, that it is a higher grade then they get a bonus?
So a Rook squad (2 dice) with a Grunt officer get a 1 die bonus, making them 3 dice.
Or a Grunt squad (3 dice) with an Elite officer get a 1 die bonus, making them 4 dice.
That is how KR 16 works as written, and places high value on officers.
(Plus good targets for snipers.)