Okay so I can see what your point is, as an incentive to be active however I do think that this will still lead to the situation where a certain amount of the player-base will get these items while those who don't, either due to the shitty nature of loot boxes or due to their accounts basically being bricked from the whole fusion costs + inventory limit thing (Yes, I am still hammering on about this) will never get them.
As I see it this can only go from ehh to really bad; if this item proves to be OP then those players who never got it are basically screwed for eternity while the lucky few who do will haul ass. On the other hand, if the range attribute proves to be too much of a disabling factor for this weapon then what was the point of investing in it. Really the only way I can see this not nose diving is if the weapon preforms mediocrity.
Ultimately the whole exclusive items idea is dumb, to prevent the scenario explained above you would need to make it a very common occurrence to try to get these items or make them preform underwhelmingly to prevent an outbreak of lucky players breaking the meta. I don't want to see another #NovaGate.