You said it wouldn't be like Overpower, but what you are describing is exactly like Overpower, without one of that skill's weaknesses: it would not interrupt your enmity combo.

Flash's enmity generation is not insignificant, does not cost TP, does not interrupt your combo, and does not require enemies to be in a cone before you. It also blinds enemies which, if they aren't already immune and you're tanking a lot of them, is handy for mitigation.

I don't see why you would need a cleave component.