Smn is plenty powerful, if it's being used correctly. Even post-nerf, it has excellent stopping power if it is allowed to cast freely. The nearly constant barrage of status effects and chip damage is a nightmare to deal with. The only saving grace is that it is generally a glass cannon. It's no surprise that it has the potential to under perform in a smaller, arena, setting, where it doesn't have a swarm of teammates to hide behind. Blm suffers the same drawbacks, and they're being nerfed further, not buffed.