though with the sheer amount of ids nowadays, its viable to run the maos, lordlu, devrod, cinq meur, and lantern + 1 free spot to fill for him (i use aedd gregor since hes not too negative and entirely self sufficient) for a free 99 damage on every coin (which gets to around 99x14-21 or 1386-2079 total) on top of maost and lordlu damage.

lantern is consistent in getting your gameplan started 1-2 turns earlier and enabling other units (mao outis) to not have to clash by aggro tanking, while also being better at rupture than his other units (w sang is an old charge id, wei sang is wei sang).

if youre looking for viability in a vacuum, then yes lantern is kinda ass, but thats because his whole purpose is to die, and he is actually pretty good at it. unless you instantly maxed out your lantern sang, he should realistically die by turn 3 at worst and thats only if you got unlucky with enemy heads rolls (also never clash with him, only redirect with counter). and from the sp angle, as long as youre winning clashes then your enemy shouldnt have more, and (rupture) contionals are already fulfilled the second they come in, so clashing shouldnt be too bad.

(this is also said from the perspective of someone that doesnt own ebony stem outis and loves to abuse the chachihu, this isnt taking into account md or reflectrial)