You fail to realize that different LBs would have to function differently and do different amounts of damage and have secondary traits.
Why do they have to do that? Why can't they just have cool-different animations? Give SMN an AoE the same size and damage as Meteor, just, ya know, with summoning-skills? Give DRG a non-punching single-target LB with the same dmg potential? Idk why they couldn't do that for funsies.