There isn't much to nerf anyway... If you want to keep the mechanics that is (SCoB's nerfs didn't remove the mechanics, they just made them mostly insignificant)
Can't nerf T10's vulnerability (maybe remove thunder's AoE effect ?) without making it useless to stack (echo will already allow for less people to stack)
can't nerf T11 (well, maybe the cube's AoE can be nerfed)
T13 will probably not be nerfed at all besides echo
can't comment on T12 as I've never tried it (was stuck on T11 and sub ran out

), but from what I've seen on some streams, only bennu's damage and maybe the brand of purgatory could be nerfed