Traditionally Conan lore wise has been a low magic setting.No fireballs. 3-5 minute casting time for a sleep spell (With 3 wizard casting it all at the same time.) Sorcery was mostly mind control and enchantments in the world of Conan. Magic made people go insane (we have a corruption system that is a great substitute for an insanity system.) Alchemy works pretty much as well as it did in the source material. And crafting undead doesn’t break lore too much.
All in all conan was about as low-magic as Tolkien, actually even lower than that. I feel alchemy already does what it needs to for a offensive magic system. With witch-doctor, animal pens and the like added it works as a rough mind control system.
In the movies Mako was more of a lore master and alchemist (and a bit of a necromancer.) Sure he had that one telekinetic battle with an evil wizard, but that was the most you were gonna get in a wizards duel.
I would like subtle magic that fits within the lore. Night vision (we have potions), Water breathing (potion) invisibility (cheat code), minor buffs (we already have elixirs) and even maybe a sleep spell. Honestly the admin panel is kind of “magic” now that i think of it, they could even rip some of the cheats and tie them to corruption so non admins can use the powers with a price.
Regardless, you think (insert weapon you don’t like) are broken? Wait till you eat a game breaking bolt of fire to the face. No thank you. We have trick arrows and bombs, I like that just fine. Oils to coat my weapons would be nice tho.
Keep it low magic, keep it within lore, and ultimately it will work out fine.