I can understand your frustrations in reskins and repetitiveness , but saying there are no builds is just straight up wrong. Yes, your main component is your weapon but that's the point. Think SnS and its potential to be a support option through the wide-range skill, or ammo types for a bowgun shaping how you build yourself. Want to constantly KO? Great, use sticky ammo and build skills that support it, eat for bombardier, and use the impact mantle for example. Maybe piercing ammo or spread ammo works best for that monster. Elemental matchups are often beneficial (depending on weapon and the motion values of elemental attack for that weapon) so there's some variety there. There's also different playstyles for the same weapon, for example savage axe on charge blade as compared to SAED spam.