I'm always on the lookout for interesting complications around how a game implements magic use. My POV is that if you don't distinguish magic from other ways of playing the game, then what's the point? Take a bog-standard example, familiar from nigh unto every high fantasy role-playing game ever made: magic missile. If casting the spell is just a matter of rolling a skill and marking off a use, and the effect of the spell boils down to damage done at a distance, then what distinguishes the spellcaster from an archer? You can gussy it up with some descriptive narration, but unless you're being very creative with the results of the move, that's strictly cosmetic. What I look for are ways in which the procedures of the game distinguish magic use, while at the same time distinguishing the world of the game from mundane reality. Two solid ways to achieve those goals are to attach risks to spell-casting, and to encourage players to make their magic-using characters into weirdos.
ARC, which recently arrived in the mail, uses a pair of interrelated rules to make magic risky. The first concerns initiative, sorting the moves you might make in conflict into five categories and ordering the action accordingly. Spells and special techniques come fourth in the line-up, which means any character attacking will do so before the spellcaster can follow through on their spell. As with all other risky moves, spellcasters must roll under a Threshold Number (TN) if their spell is to succeed, but a second rule turns the screw: each attack on the spellcaster lowers the TN for successfully casting a spell. The lower the TN, the lower the odds of rolling a success. Effectively, what's simulated here is the difficulty of concentrating on the work of magic as the conflict escalates. This gives substance to the conceit that focus is required to work magic, while also loading the decision to cast a spell with a degree of tension.
That distinguishes ARC from other games on the tactical level. In terms of role-play, ARC encourages weird characters by making ritual behavior a condition of recharging spells after use. The prescribed rituals are usually analogically related to the spells they restore. So, for example, to replenish the Windstep spell, your character would jump over a newborn. Like a weirdo. (I use “weirdo” here not only affectionately, but also diagnostically; initially meaning “fate” or “destiny,” weird is the word Middle English speakers used to describe the control of destiny. The “uncanny” connotation is reportedly Shakespeare's influence, and the pejorative sense is a result of the puritanism and disenchantment of the modern era.)
Those ritual prescriptions not only force players to approach magic-use more deliberately; they also push them to shape their characters' behavior around a strong underlying conception of how magic relates to the world. To be successful as a magic-user, you must play ARC as the sort of character who would jump over a baby, or cover yourself in ash, or spend most of the day skulking in shadows. I'm a little skeptical of the spells that require ritual behavior of the player, as opposed to their character, but the rules mark those as negotiable. And for gaming groups who balk at the prospect of jumping through those hoops, there's an option to play with rest as the sole requirement for replenishing spells. I'm sure that's more convenient, especially for the GM who has to narratively conjure up a newborn every time a player wants to prep Windstep, but it also undercuts what makes ARC's magic, well, magical.