I've been reworking the Sage class into something a bit different lately. I still like their focus on Support, and being the most 'magic' class despite not having spells, but I've also wanted to increase their focus on knowledge and taking away their inexplicable magical powers.
So instead; here's a nonmagical version of the Sage.
Class HD- d6
Add Level to Magic Saves.
Instead of casting spells, the Sage uses knowledge to aid their party. They can identify magic items and also learn clues about tracked monsters. They are the best at brewing magic potions, gaining +1 per Sage level to the potion's effect roll, and can identify their ingredients easily.
Instead of casting combat spells, Sages can use magic rods like everyone else. But a Sage can also bind themselves to a single magic rod, which increases its charges by +1d6. The Sage can cast some minor cantrip-like magic that requires no charges even if they don't have the rod, as long as it isn't an attack. The magic is inherent within them now, until the rod is destroyed.
Finally; Sages get +1 to their magic roll per Sage level; which are done when using all sorts of magical rituals, items, spells, crafting, crossbreeding, and all other forms of magical actions.
Magic User Titles
All “magic users” or Sages are the same class. The different names are merely titles, depending on what they know and do.
Sorcerer is a catch all term, with a connotation of some respect.
Wizard is an official or employed magic user, usually acting as a court Wizard; a magical adviser and specialist for a ruler or lord. Mages or Magician is used for an employees magic user in a lesser role, such as working for a guild or smaller entity. Battlemage is one that fights in an army.
Witch is a term for an unscrupulous or lowborn magic user. Has a female connotation, but Witch-Men and Witch-Kings are just as common.
Warlock is a term for a magic user who joined a magical order, coven, or guild and stole knowledge and power from them before leaving. It's one of the worst names to be called, and bounties on Warlocks are common in magical communities.