In D&D, with an AC system that directly ties into to-hits, this is very pronounced. D&D4 had a system where level directly ties into the to-hit system; and it was very difficult to get hits in, especially if your equipment was not up to the level you were at, or if the monsters were 4 or more levels above you.
We struck a middle ground, keeping whiffs high, but you can mitigate this and get a better to-hit through positioning. They aren't as high as beginning D&D, an average low level character has a closer to 40-55% chance to hit, which feels right. Armor does not subtract from to-hits, but there is a chance a blow that lands will cause little or no damage if the target's armor is high enough.
An important note, and one we found is a necessity. All spells and powers require a to-hit, even beneficial party spells such as buffs and heals. Players used to modern MMOs and RPGs may find this strange, since beneficial spells are assumed to auto-hit. This is controversial, but needed for two reasons.
- This raises the importance of a character's casting skill
- This prevents deadlocks in combat
Monsters that have healing powers also need to roll for them, in play testing, we found a goblin healer in the back ranks could tie up the combat for a long time by spamming heals. Putting an uncertain factor if the heal would land made the combats more fluid, and eliminated the chance for deadlocks and long combats. This is that chaos factor coming into play, and it raises the importance of high-skill healers and casters.
Of course, the chance to cast is affected by referee-set difficulty modifiers, so if you are in the field with no monsters around, a referee could always apply a simple or trivial modifier to the casting roll, since there is no pressure to cast the spell quickly and without someone trying to kill your character. In combat, things change, and caster skill becomes an important factor. Highly skilled mages and healers are important allies, and also formidable foes.