The FR 5.56 in its original game MW19 is a burst-fire weapon.
In CoDM this gun has zero uniqueness as it's almost identical to the BK57, Kilo141, CR-56 AMAX etc being just another mid-firerate AR.
I've almost never seen anyone use this gun and it's not hard to know why, it's just a boring gun.
Adding a burst perk or attachment to this gun would give players a choice to add a new fun element to it, making this gun potentially deadly with a well-placed burst while requiring some level of skill.
This would also make the FR 5.56 a solid alternative to the M16, which is currently the only burst-fire AR in the game (Swordfish doesn't really count imo as it handles way differently.)
The devs updated the FR animations last season (which look and feel amazing) so that gives me hope that they would show some love for this gun.
Anybody else with me here? Or if you disagree I would like to know why.
TL;DR: It would make the gun more unique, adds more fun and variety to the gunplay.
(pic above is just a sketch)