Increasing Unexpected Courage cost to 3 would kill it.
I actually tend to agree in a way, I would think hard before playing it for 3 resources, the difference between two and three is substantial. I do not think it would be a bad card by any means, but I prefer the "uniqueness" of sorts, either 1 per deck or similar. It is strange that cards like Unexpected Courage have no requirement whilst inferior cards (in power) do. I think it comes from the early mistakes in the design. And it is exactly these mistakes that need to be corrected. I mean Beravor did, Protector of Lórien did, even Expert Treasure-hunter. I believe UC is much more obvious target because it has so many "peers".