DnD 4E Rules I Don’t Like [II]: Natural 20 & Critical Hits
From page 278 of the PHB:
Natural 20: If you roll a 20 on the die when making an attack roll, you score a critical hit if your total attack roll is high enough to hit your target’s defense. If your attack roll is too low to score a critical hit, you still hit automatically.
From a realism perspective, this rule is fine — even though the 1st level Fighter rolled a natural 20 to hit the Ancient Dragon (and thus scored a miraculous hit) she shouldn’t do critical damage because it was a fluke that she could even hit the dragon. But from a game perspective this is just an additional rule complication that shouldn’t be necessary. Just about any opponent you face should be able to be hit by a 20 + your attack bonuses (and the reverse). If not the encounter is not balanced properly. Why not just simplify matters and have a 20 always be critical?
Natural 20: If you roll a 20 on the die when making an attack roll, you score a critical hit.