I have spoken before on the limitations of the Magic-User as described in the 0 edition of the world’s first fantasy RPG as well as the Magic-User as presented in the retro-clones of the OSR. Simply put, while the Magic-User is awesome near the end of his life span he generally is a let down early in any long running campaign. The spell growth of the Magic-User, as well as their limited ability to cast those spells per day makes them of limited use in combat situations. These limitations with vanilla spell-casting especially come to light when playing with kids and their preconceptions on magic and spell-casting.
In the last ten or so years magic has moved away from being something of long study, concentration and a dedicated spirit in popular fiction, movies and books. Magic is something born of the wielder, something that the user can use on some instinctive level and is always a part of them. Harry Potter in his first year at Hogwarts did not cast a single spell and then yell for help. He was inexperienced and had little knowledge of magic, but he was able to hold his own in magical battles. As he aged and learned, Harry got better at his casting, but from the beginning he, and presumably all wizards, had talent enough to hold his own in multiple battles without needing to rest for eight hours and read over his spell book.
On top of Harry Potter there are popular, kid-centered games, like Wizard 101. In Wizard 101 every combat situation finds the player with the ability to cast/summon multiple spells, creatures, buffs and attacks. These attacks are then refreshed between every combat situation making it so that the player never has to bow out to study. From level 1 the player in this game can expect to have a tough but good chance of being able to survive combat and be able to continue on their private adventures. As they grow they get stronger and learn stronger spells, but, as with Harry Potter, they don’t need to retreat so easily even at the earliest levels.
Spell books and the need to read those spell books is another item that hangs my child players up if I can get them past the hurdle of the “cast and forget” aspect of the class. They can grasp that the spells have a “cool-down” but the amount of time frustrates them to no end. Typically explaining this aspect of the rules elicits responses of “that’s no fair!” and “does the fighter need to rest that long after he uses a sword?” Personally I don’t find it fair either, and that has always been one of the contributing factors to my constant use of fighters and barbarians when I play instead of GM.
In the past few months I have worked to make a more modern Magic-User in the OSR without sacrificing or complicating the wonderful simplicity of OSR rule sets. My primary reason has always been about my players even when the results aren’t (see the Blood Witch) for them.
Currently I am working on a Rune Caster, a magic user who infuses runes with nature spirits and the quintessence of the world itself. The runes can be etched into anything, and the caster can have up to ten runes. More severe magicks may take more than one rune. To etch a rune the caster need only know the rune and succeed in a spell-based saving throw (spell level + ½ character level + 10). In my mind this emulates the feel of the card-based spell combat in Wizard 101 (or if the player wants to just summon things, Pokemon). Thus far I have only play-tested the Rune Caster on my daughter so it is no where near complete enough to post even an alpha version here or throw into the mix in the weekly S&W game I run for her and her friends.
However, one thing I have done in the weekly game is inserted two magic wands that can hold up to 7 spells of the character’s choice (and level) and can be recharged by the player tracing the spell symbol onto the wand once every 24. If she wants a new spell she just has to trace its symbol instead.
For me making the default Magic-User fun and fast for my child players has been a long and sometimes annoying battle. However, it has also given me some of my prouder moments as a hobbyist designer and as a GM.