I prefer to regard them just as metagame abilities.Encounters and Dailies for martial characters aren't REALLY that hard to look at in a way that makes sense.
What is the difference between a Brutal Strike and a Reaping Strike, in game? Nothing. They're both hits by the fighter. The Brutal Strike is just a slightly more brutal one. What the mechanics do is let the player of the fighter decide when his/her PC will achieve a slightly more brutal strike, by letting him/her choose to use the daily rather than the at-will.
What is the difference between hitting two targets with a close burst, and hitting target A with a melee attack in round 1, and then hitting target B with a melee attack in round 2? Nothing, except that with the close burst the fighter got lucky, or struck slighly more quickly, or . . . (This actually helps to reduce the sense of a stop-motion world that a turn-based combat system can tend to engender.)
Now some ranger and rogue powers that impose conditions (blinded, weakened etc) perhaps do have to be narrated as special moves, but they are a minority of overall martial powers. And even then there's nothing stopping the player of the ranger characterising every attack as an Excrutiating Shot - it's just that only once a day is it so excrutiating that the target is weakened!