[@Cube]
No, no. I do not actively criticize your game.
I am merely asking how is playing a mage [i]incentivized [/i]in this game? As you've assumed, in your vision of classic high fantasy, there is no reason for a warrior to be a warrior because he can, allegedly, simply study some magic and buff himself up.
In this game, what are the reasons for a wizard to take up the path of a wizard instead of learning how to comfortably wear heavy plate and carve his enemies up with a sword? All that a great sage can do after studying his entire life is casting and controlling man-made fire - seems incredibly lackluster and utterly useless when one can dedicate his life to becoming a renowned lord and having an army and onagers that hurl urns of greek fire at the enemy at your command, to use your own analogy.

I've no qualms with "low magic" settings such as Conan's universe, but I would like to note, that in these settings, magic is not, ah, "low-powered" or "not-almighty". Magic in the world of Conan is extremely powerful, extremely dangerous, but just as extremely rewarding for those who dedicate themselves to it. On a personal level, all that a sorcerer can do is indeed, mere cantrips - quickly and impressively fulfilling tasks which any able-bodied man could've managed without much trouble or performing parlor tricks, in addition to perhaps having several previously prepared charms at his disposal, such as a sorcerous tattoo that turns into a horrible snake or a necklace of fingerbones that grow into skeletal warriors that protect him when thrown onto the ground or rubies filled with liquid fire in his rings that explode like horrible bombs when thrown, but the true POWER of sorcery in "sword and sorcery" genre comes from horrible and dreadful ritual magicks which take months or years to engineer and produce world-shaking effects. A sorcerer can turn himself immortal, after a fashion, create an army of demon-blooded soldiers wholly subservient to his will, rain meteoric fire onto an entire continent or project his soul into the body of a king, and usurp the country.

 Like, consider Thulsa Doom. Dude was immortal but when he was pierced with steel, it caged him and prevented him from acting up. Dropping that, in person he could hypnotize with his gaze and change faces and voices. But when at his citadel and not interrupted, he could weave world-wreaking magicks, given time and rare and mythical ritual components. Not to mention that he was actually a capable swordfighter.

Thoth-Amon, a physically mighty giant and likewise a sorcerer, had similar abilities. In person, at a moment's notice, he could produce mere parlor tricks, but with preparation and given sufficient time, he could turn a man into a slave of his god with a whisper and a handful of dust, not to speak of incredible rituals that he could, again, commit if given time. The only limitation of the ritual magic was the fact that if it was somehow wrong, un-precise or rushed it would kill you in a horrible fashion and that it required terrible sacrifices, anywhere from the blood of a thousand virgins to giving up your own eye, arm and leg.