[dataweaver]

In simplistic terms, the Cult of Ecstasy is your Bards: sex, drugs, and rock and roll is how they do their magic. In similarly simplistic terms, the Euthanatoi are necromancers, with a specialty in reading peoples’ fates so that they can tell when a person is beyond redemption and deserving of being put to death.

Conceptually though, this notion misses the whole point of Mage, which is that everyone is ultimately doing variations of the same thing. For instance, the Hollow Ones aren’t psychics; they’re dabblers — magical Jacks of all Trades and masters of none. Meanwhile, each of the Traditions has mastered one flavor of magic. To capture that aspect of things, you really should have a common core system shared by all of the Traditions — although the details of how that common core is implemented can and should vary from Tradition to Tradition.

In that regard, I’d use a combination of Realm Magic, Magical Styles, and GURPS Powers to represent individual Traditions. For instance:

• The Order of Hermes would have Magery as a Power Talent, “Magical” as its Power Modifier, and various Realms as its Power Abilities. It would have Thaumatology as a core skill which would serve as a cap for the various Realm Skills. Style Familiarity with Hermetic Magic (which features the Forces Realm) would provide access to a selection of Style Perks that further modify how their magic works.
• By contrast, the Celestial Chorus would have Power Investiture as a Power Talent, “Divine” as its Power Modifier, and various Realms as its Power Abilities. It would have Theology as a core skill that serves as a cap for the various Realm Skills. Style Familiarity with Theurgy (which features the Prime Realm) would provide access to a selection of Style Perks that further modify how their magic works.
• Then you have the Dreamspeakers, who have a “Sensitivity” Power Talent, “Spirit” as its Power Modifier, and various Realms as its Power Abilities. They would have Ritual Magic serving as a cap on their Realm Skills. Style Familiarity with Animism (which features the Spirit Realm) would provide access to a selection of Style Perks that further modify how their magic works.
• The Etherites would have a “Genius” Power Talent, a “Super-Science” Power Modifier, Realms as its Power Abilities, and Weird Science as the cap on its Realm Skills. Style Familiarity with Ether Science (which features the Matter Realm) would provide access to a selection of Style Perks that further modify how their Science works.
• The Akashic Brotherhood would have a “Dharma” Power Talent, a “Chi” Power Modifier, Realms as its Power Abilities, and Auto-Hypnosis as the cap on its Realm skills. Style Familiarity with Ascetic Magic (which features the Mind Realm) would provide access to a selection of Style Perks that further modify how their magic works.
• The Verbena would have a “Sponteneity” Power Talent, a “Nature” Power Modifier, Realms as its Power Abilities, and Herb Lore as the cap on its Realm Skills. Style Familiarity with Witchcraft (which features the Life Realm) would provide access to a selection of Style Perks that further modify how their magic works.
• The Virtual Adepts would have an “Arete” Power Talent, an “Augmented Reality” Power Modifier, Realms as its Power Abilities, and Computer Hacking as the cap on its Realm Skills. Style Familiarity with Reality Hacking (which features the Correspondence Realm) would provide access to a selection of Style Perks that further modify how their magic works.

And so on. Everyone uses the same core system (i.e., Realm Magic); but each tweaks how that system works through the selection of Power Talent, Power Modifier, core skill, primary and supplemental skills, Style Perks, etc. (The Hollow Ones would differ from the rest in that they’d lack much of the above: no Power Talent, no Power Modifier, no core skill, no Style Perks; Realms would be purchased “raw”, and Realm Skills would be capped by a 10/level Unusual Background Advantage.)