Again, it depends. It can go both ways but it can also not. Say there is content you can't clear with Hercules without her weapon, what are the chances you could clear that with another soul without their weapon but one who provides more team utility like Joan or Mordred? I think there's a good possibility that you could.
For the person asking for help with his dark team, I already brought up my opinion if he grabbed Thanatos. Shingen or stick with Mordred if he ISN'T going to get Hercules' ax. He doesn't have Shingen yet and mentioned he's going to hold on Hercules' ax, though this discussion we've been having might change his mind. If he goes Thanatos+Shingen, he can use Sniper Shot and replace Lu Bu with Susanoo while still having all and more essentials than a Hercules' team of the same composition. Otherwise, yes, the other set ups are more or less what I would suggest too.It's not only about 'missing' Kamihime. You can have some debuffer Kamihime and you may want Axe because it'll let you replace her with someone else. Such is the case with mentioned before dark team. Dejnov has Susanoo, Osiris and debuffer SRs (Lu Bu, Nyar). If you'll get Thanatos and go for all-hime DEF down, you'll have to throw either Susanoo (most probably) or Osiris.
Tbh in this situation I'd either go with Mordred/Thanatos/Susanoo/Nyar/Osiris for balanced team, or Herc (with at least 1LB axe)/Thanatos/Susanoo/Lu Bu/Osiris for offensive (for some BT raid kicking or when team is ready to set Mordred aside).
Having free hime slots is good but there's no point in having them if you don't have anyone good to put in those slots.