There's a D&D 4e variant rule where all powers are Reliable, meaning you don't lose your Encounter/Daily powers if they miss. If a power has an effect on a miss, you may either accept the miss effect, or forgo the effect and retain the power. There's an alternative which charges one healing surge to recover the power.
The intent of the rule is to make it less frustrating to waste a limited-use power due to chance or poor character optimization for attack bonus. I suspect it also shortens long boring combats by keeping encounter powers longer so they don't turn into at-will grinds, but it may also lengthen them by keeping more options in play.
Is "All Powers are Reliable" too powerful? Is it necessary to charge a healing surge?
Best Answer
No
There's been discussion here to the effect that reliable fireballs simply don't make sense and that it reduces the fighter's uniqueness. Given that dailies are reliable or have miss effects, it's not fair to be able to decide if half-damage is acceptable at this time.
Encounters should not be made reliable: they are usable every combat and while it's disappointing to miss with one, you can quite literally try again the next combat. Encounter powers are intended to be signature items. By flailing around (again dliuting the already reliable powers) until you hit with your chain lightning... characters lose the iconic significance of their powers.
However, if your players really don't like missing and aren't willing to increase their accuracy, allowing them to spend a healing surge for +5 before the roll is a way to make sure that "I really need the power to hit" moments are valid. I wouldn't use this house rule in my games, but it is a fix that doesn't dilute the nature of reliable.