One of the cooler ideas yet from D&D Next: an iconic fighter ability called Combat Superiority.
As presented it’s got a lot of potential. Essentially the fighter has some dice that scale with level and depending on their choices they can apply those dice different places: a defensive fighter might be able to apply them to damage reduction, etc.
Here’s a few uses Mike mentions:
Damage reduction for the fighter
Spend for damage reduction to someone else
Spend to make an attack out of turn
The best part about this mechanic is how many other uses it inspires. Off the top of my head:
Added movement distance