the thing is that Naberius and Alaude (in the RDM continuity) and Savoulain (in the SGE continuity) are capable of acting as Lucent's impulse control in a way the Scions wouldn't be able to, at least not for a while
namely:
- Lucent's "canon" pals are proactive about keeping Lucent out of situations where he is tempted to use violence on another person, along with finding safer outlets for his impulsiveness (monster hunting, less-dubious medical science, etc)
- meanwhile the Scions are aiming the WoL directly into the heart of a lot of Fraught Societal Situations and pulling the trigger over and over
- Lucent's "canon" pals know him as an individual very, very well and thus can input the Konami code that gets Lucent to stop smashing a fucker's already-smashed face in and go do something else. I personally don't feel like the Scions really bond with the WoL beyond "this cool mercenary we recruited" until like... Heavensward at the earliest? especially Alphinaud
also, while Lucent is strong, he's not WoL-level strong and does have plenty of fights he would lose. if you gave him the WoL's strength it would be that much harder for him to not see violence as the solution