I have a hunch that dragonstone crackclaw and Kings landing will feature very lowly in other houses 7 Castle lists apart from martell (and stark with crackclaw)
I suspect this is because two of baratheons immediate neighbours, tyrell and lannister have no practical way to take dragonstone. This means that a counter attack backed by sea support awaits the brave player who dares take the stag homelands. I personally find them a lot harder to keep than take when fighting baratheon