I'd make it more of a 'this rune can/is/will be more than X% efficient in comparison to it's cost.' (Hint: nora gen too)
I think OP as heck (cause I dont like saying the other word) basically means it needs to be nerfed ASAP, whether if it needs 50 nora or 5 is up to you.
If I ever use this expression seriously I am meaning that I believe this rune, or most likely some runes in a combo need a redesign, for a cost hike will just mean that winning the game got more expensive, but not undoable.
not really, just poor design. it should have a cap on the number of free attacks it gets and when it doesn't proc that ability its pretty weak. it should be stronger relative to its nora cost when not using its signature ability and the ability itself should be nerfed or at the least have a cap.