Yeah, I was thinking about that as I wrote it. I know on Mondays, my guild kicks out a ton of keys - yesterday it was like 400+. Do I really want to have to go through 400 new cards to update it? And then when I ascend a troop, I need to update it again?
The answer was "ugh, kinda :/"
Another thought (now that I've finished putting everything in): on classes, maybe a checkbox to flag that you obtained the weapon? I don't know what DB you're using (SQL or NoSql) so I don't know how much of a PITA it is to add a new field like this; this is something that I think would be good, but also not terribly important.
(I'm really torn on the original suggestion; I'm sure it'd need adding a new field or something, but I almost want it enough to where it'd be worth it.)
And I agree - some kind of user API would be awesome for this Even if they just worked something out with you specifically and didn't make it actually "public", since you're obviously dedicated to this community.