My apologies if this has already been suggested and I missed it. What if we errata the Tin Link with the text Discard Tin Link … This would allow the Tin Link to still be repeatable with the Bronze Link. However, it would slow it down and require a bit more effort. I'm not sure it fixes all the problems associated with the Tin Link but it might not be a bad start. For instance, I still wouldn't be willing to build a deck around an attachment. But I would be more likely to include some great attachment like Taste for Blood or Widow's Wail. Any thoughts?

It's an interesting idea, though I think there is a critical flaw. In a deck with Bronze Link, you can basically have no change. In a deck without Bronze Link, Tin Link is one time use.

I would ask you what the desired effect is? If the desired effect is for Tin Link to matter, but not be repeatable, it would almost be better to just have it's effect remove itself from the game after use. It's high impact, but still fragile and would have less of an impact on lesser attachments as you always have to debate "Is there a big ugly that I need to save this for?"

I like your idea, it is certainly different than the suggestions I've seen for Tink Link.