Ever have that moment where you go into a dungeon and realise "oh joy 2 archers, now we have to do this without a DD limit break"? I've never been in a situation where the archer having healer limit break has been a life saver. Sure some will argue on HM primals it can but I can't say I've been in a situation where both my healers have been KO'ed and the archer limit break could turn the fight around.
For a ranged limit break I'd suggest a single target attack weaker than the DD one but stronger than the Mage one with a new additional effect exclusive to the limit break.
Examples:
Aerial missile: 1900 potency, single target, additional effect: pin 15s. Character launches a shot into the air large missile comes Down on the target.
Bombard: 4000 potency, single target, additional effect: pin 20s. Character fires rapidly into the air a hail of shrapnel comes down on the target.
Radiant storm: 7500 potency, single target, additional effect: pin 30s. Character fires a bolt of lightning into the air, comes down on the target.
Additional effect: pin is basically silence, pacify and a bind (that won't be broken by attacks) and no mobs have immunity/resistance to it. The mob can still auto attack and it won't stop it using special moves like hellfire, aerial blast or earthen fury. But if they do use a special move the effect will still be active when they finish the move.
I see this add effect being used as kind of a breather move. So if everyone has taken a lot of damage you can use this limit break to basically halt the mob while your party all get away and recover for a few seconds.
I just don't think that not having a ranged limit break will work out long term. More ranged classes will eventually be added (musketeer) and they can't all just get healer limit break. It would be better to change it now and give it to archers and have it there for future ranged class releases.