Yes, they use enchanted fetishes and so forth, but in my campaign this does not replace Runes. As I've shown, the Runes can be used to describe shamanic magic as well. Blueface was from Griffin Island. His runes were tattooed onto him. They only represented enchanted spells, however. What I propose is a more in depth Runic system.
You see, if you go by River of Cradles, then Zola Fel inscribed his runes into the PC's prior to the beginning of the adventure. It makes sense that Zola Fel has dominion over such Runes as Water and Mobility. He's also acquired Harmony and one other one I can't recall at this moment. So Divine magic in the old system comes from the fact that the Gods have knowledge of Runes. They can grant the effects of Runes onto their worshippers. When an initiate reaches high enough committment to his god he becomes a Rune Lord. The God gives him the knowledge of that gods Runes, making it so he can cast spells himself, ie reusable. He now knows the Rune himself and no longer needs his God to grant them to him.
It was this knowledge that allowed Arkat to go from one cult to another, become a Rune Lord in each and acquire a vast range of Runes. Knowledge of all these Runes gave him combinations that allowed for spells that did not exist in any one cult. That is how he became so powerful. Once he became a Rune Lord of a cult, he no longer needed that God because he'd now learned that Gods Runes and could use them himself, directly. So he'd move on to the next cult and start over. This was his way of Questing For Runes.
What I'm proposing is using Runes as the derivative of all magic in Glorantha. A Sorceror pulls the power from within himself. This suggests that we all have access to the Runes, but only sorcerors understand how to access them. Divine magic means a God who already has access to the Rune passes it to his followers. Shamans seek out spirits that have access to Runes. A person could, in theory, become like Arkat through shamanism or sorcery. They'd RuneQuest in a different way than Arkat but the final results would be the same, access to far more Runes than any one God.
Therefore, all spells castable in the world of Glorantha can be ascribed to specific Rune combinations. The many complex combinations of Runes all produce specific and unique results. The Runes change reality, ie create magic. If you gather together the Runes, you have wider and wider diversity in spell choices and more powerful spells from larger combinations. To Enchant things would require knowledge of the Stasis Rune whether you be shaman (who accessed knowledge of the Rune from a spirit), a Rune Lord who was granted knowledge from his God, or a Sorceror who studied the Rune Stasis and acquired the knowledge for himself.
This allows me, the gamemaster, to limit spellcasting in whatever ways I seek, because I can limit access to Rune knowledge. In a typical tribal setting, only the Shaman would have any knowledge of Runes at all. The spirits he would summon could grant spells, but not Runic knowledge, so unless you could bind the spirit, you cannot cast its spells. Gone would be the old RQ2 method of summoning a spirit and using spirit combat to force it to give you its spells. You must acquire the Runes for that spell first. The spirit could be bound to an object and forced to cast the spell, but it cannot teach you what you'd need to know to be able to cast it yourself. Only a huge committment in time and study, heroquesting or the grant of a God could give you that ability. No more games where everyone casts magic, though some spells would still be somewhat common. Stasis would be a very commonly known Rune amongst shamans, sorcerors and Priests as it would allow enchanting.
What Runes the tribes shaman did know would be passed down to his apprentice. This would create the need for Ancestor Worship and be the driving force behind the need for such worship for if anyone died before passing down their Rune knowledge, this would allow their spirits to freely pass on that information to their descendants. So the tribe would not lose it's most treasured resource, knowledge of Runes.
A character like Blueface the Shaman would be extremely powerful, not because of all his fetishes and whatnot, but because he actually would KNOW Runes. He'd have acquired them. Thus the Runes all over his face. Since he doesn't belong to any single tribe, his knowledge could conceivably be lost should he die before passing down all this knowledge to his descendants, one of whom is given in the game but I forget who that was. Naturally, he has been teaching his child as much as he knows.
Forcing Rune knowledge from a spirit should be impossible. No more summoning a spirit and engaging in spirit combat to learn its spell. Instead, you'd have to go on a quest of Heroquest proportions to find and acquire any new Runes. This is how the seas were finally reopened. The correct combinations of Runes had to be found to cancel Zzabur's magic and reopen the seas. Many would have died trying to find that combination because Zzabur would have been activiley protecting that knowledge from Rune seekers.
Having learned how to reopen the seas, Dormal could now Deify himself because he alone would have the knowledge of the Runes needed to overcome Zzabur's Closing. Therefore, he's now in the position to pass that knowledge on to other Mariners by exacting a price in worship. He's thus become a God. Any other Rune Lord could take that knowledge with him and go to some foreign land and open the seas to those people and thus deify himself because now they'd turn to him as a God to pass that knowledge. But in lands where Dormal is worshipped, people would already turn to Dormal, why worship a dead Rune Lord? And thus, different lands develop with different Gods who basically do the same things. People call them versions of the same God but in fact, they are nothing but opportunistic Rune Lords of the original person who discovered that Runic combination.
Ultimately, however, all Rune knowledge can be traced back to the original, most powerful Gods. The First River (Styx?), Yelm, etc.
The God Learners would have been doing strange things to Runes. Making experimental combinations and observing the results. This would have caused major disruptions in the very fabric of magic. Runes, afterall, would be very symbolic and exploring the symbolism and how it relates to actions upon the God Plane would have been at the heart of such experiments to find new Rune combinations and thus, new magics.
So in my campaign, all the different types of magic ultimately come down to the Runes. Afterall, the game IS called RuneQuest.