rmcoen
Adventurer
The Sword of Truth series has wizards. Wizards who primarily work subtle spells (Wizards's First Rule), but can also participate in warfare. One casts a spell that seeds the air with microfibers of glass, to slice up the lungs of an opposing army... which is then blown backwards by (a really big) gust of wind, prompting the saying "a war wizard's primary purpose is not to inflict harm on the enemy army, but to negate the other army's war wizard..." I.e. most of the wizards' time is spent cancelling each other's spells, so it comes down to martial power anyway. But an unopposed wizard rules the day. And no, I don't recall any failed spells by wizards (excepting the main character, who refuses to accept his wizardry for, oh, the first 5 books).
Most other fiction that I recall has the enemy spellcaster always successfully casting a spell, but sometimes it fails to affect the hero because Hero (saving throw / fiat / deus ex). Unless it's the world-altering BBEG Evil Ritual (tm) that the story is all about stopping, in which case, they generally stop it. Most of the time, though, story Heroes are the brawn, struggling against the powerful mage.
I like that 4e martial characters have similar power and options to 4e spellcasters. The fighter and his magic weapon can hurl one foe back 20' to 30' with an at-will attack (depending on the item's level), draw all foes within 15' to adjacency, then spin around slicing all of them for one hit. (an encounter power). If he wanted to spend an Action Point, he could spin around and hit them all again (a second encounter power). The wizard can cast fireball, of course, or a lightning bolt that hits any 3 targets, or several other variations of damage dealing, including an at-will that causes 15' diameter explosions. Or he can move foes around with magic, push them away with magic, summon them to a specific square (not his own) with magic, and so on. The wizard can impose and remove vulnerability, or summon a couatl, abilities beyond the fighter; in contrast, the fighter can shrug off a 20-damage hit, or "armor up" and give himself Resist All 5 or 10. The Cleric can reverse killing blows, heal the whole party at once, and even cause constant damage to foes. But everyone has things they can do of equivalent power.
And they are always successfully *attempted*, failing to achieve results based only on the target's defenses. Wizard spells are just as reliable (or unreliable) as fighter powers as cleric powers as...
Out of combat... even in 4e, spellcasters tend to have an advantage. The Wizard can reroll some skill checks, or substitute Arcana for certain skills (like Diplomacy, i.e. Charm Perosn) -- but this is because he sacrificed a combat power slot for a more generally applicable power. But there is still potential balance -- any character has the option of taking a Skill Power for a skill they are "Trained" in. The simplest are at-will "Advantage on this skill roll"; some are more varied and useful in and out of combat (like Endurance's "Third Wind", or Stealth's "end your move 3+ squares from a foe, you can reroll Stealth despite not having Full Cover").
If you introduce "chance of failure" with magic, then increase the wizard's "uses" of magic. Even if it's just "cantrips" (pick your edition/game for level of power). But really what you're going to do it just incentivize players to maximize their success chances. "Oh, I need an Arcana check to succeed in merely casting my spells? Okay, I'll put all my points into Arcana, get Skill Focus Arcana, and look for items/spells that increase my Arcana skill." (Which, honestly, is no different from the martial characters "Okay, I'll put all my attribute points into my accuracy-increasing stat, get Weapon Focus, get masterwork/magic weapons, and look for items/spells that increase by accuracy...")
Most other fiction that I recall has the enemy spellcaster always successfully casting a spell, but sometimes it fails to affect the hero because Hero (saving throw / fiat / deus ex). Unless it's the world-altering BBEG Evil Ritual (tm) that the story is all about stopping, in which case, they generally stop it. Most of the time, though, story Heroes are the brawn, struggling against the powerful mage.
I like that 4e martial characters have similar power and options to 4e spellcasters. The fighter and his magic weapon can hurl one foe back 20' to 30' with an at-will attack (depending on the item's level), draw all foes within 15' to adjacency, then spin around slicing all of them for one hit. (an encounter power). If he wanted to spend an Action Point, he could spin around and hit them all again (a second encounter power). The wizard can cast fireball, of course, or a lightning bolt that hits any 3 targets, or several other variations of damage dealing, including an at-will that causes 15' diameter explosions. Or he can move foes around with magic, push them away with magic, summon them to a specific square (not his own) with magic, and so on. The wizard can impose and remove vulnerability, or summon a couatl, abilities beyond the fighter; in contrast, the fighter can shrug off a 20-damage hit, or "armor up" and give himself Resist All 5 or 10. The Cleric can reverse killing blows, heal the whole party at once, and even cause constant damage to foes. But everyone has things they can do of equivalent power.
And they are always successfully *attempted*, failing to achieve results based only on the target's defenses. Wizard spells are just as reliable (or unreliable) as fighter powers as cleric powers as...
Out of combat... even in 4e, spellcasters tend to have an advantage. The Wizard can reroll some skill checks, or substitute Arcana for certain skills (like Diplomacy, i.e. Charm Perosn) -- but this is because he sacrificed a combat power slot for a more generally applicable power. But there is still potential balance -- any character has the option of taking a Skill Power for a skill they are "Trained" in. The simplest are at-will "Advantage on this skill roll"; some are more varied and useful in and out of combat (like Endurance's "Third Wind", or Stealth's "end your move 3+ squares from a foe, you can reroll Stealth despite not having Full Cover").
If you introduce "chance of failure" with magic, then increase the wizard's "uses" of magic. Even if it's just "cantrips" (pick your edition/game for level of power). But really what you're going to do it just incentivize players to maximize their success chances. "Oh, I need an Arcana check to succeed in merely casting my spells? Okay, I'll put all my points into Arcana, get Skill Focus Arcana, and look for items/spells that increase my Arcana skill." (Which, honestly, is no different from the martial characters "Okay, I'll put all my attribute points into my accuracy-increasing stat, get Weapon Focus, get masterwork/magic weapons, and look for items/spells that increase by accuracy...")