You can only cope for so long
Even outside of a scaling point of view, it doesn't make sense narratively to introduce a new character just to have him immediately get hypetooled like that.
With Aramaki, it at least had the excuse of being a blatant Film Red promo as well as a tactical retreat on Aramaki's behalf (even though he did overreact). There'd be no reason for Oda to have Shanks hypetool Loki, though.
Furthermore, did anyone ever say Shanks "defeated" Loki, or did he just "stop" Loki? Because this could be another Shanks vs Kaido thing where they very likely just negotiated instead of fought to the death