Look what I wrote below amid the Second Thoughts for Ingold (near the top of the page).
https://community.fantasyflightgames.com/topic/181558-reaction-series-wastes-of-eriador/
Of course, the designer had thought of it before, it just feels "interesting" to have an idea for a card, and then see it coming: less then a fortnight apart.
By the way, I had thought the attachment could be a bit cheaper but I think it is about right. If you play it early, or with a discount, the cost should pay off eventually. However, I do think you need a specific deck to make Sword-thain effective: just as those mentioned in the article or on the forum. Igold himself can get a little stronger with it.