So I suspect this is going to be a common answer to many questions. The simple answer is often the card mechanics the art team is given changes over time as design finds that they need to change a cards strengths, if the change is too dramatic we try to recommission the card and use the prior art for slush in a more appropriate card in a later set. But that only happens if we have the time and budget. So with The Sound of Thunder (a piece we didn’t work on, but I can lay out a theory based on our experience so far), it’s a safe bet that the original card mechanic had more to do with cavalry and less to do with battle maidens. Another example of this (mentioned on Facebook) is Moshi Nakata the card started out one way but over the course of playtest it was made into a Commander from a Thunder Shugenja.
So art and story in don’t not always mesh as smoothly as we want this is mostly due to the schedules of Design, Story and Art working on different time tables. Design being the longest, Art taking place in early to mid design and story having input at the start and end of design. There are times that art was commissioned for something else and used in a pinch, or the mechanics of the card changed in play test after the art was finalized. Flavor text however is a story team matter and I can’t speak to their choice of wording. The Kuronada exp 2 piece was completed by the time we came on board so the whole story and process behind it is as much of a mystery to us as you. But I agree perhaps some choice of words could have been different to convey the parallels between the two characters more clearly.