It's kind of a shame because their designs are so cute.
この場合、次のような言い方ができます。
ーIt's too bad because they have such nice designs.
「せっかくいいデザインなのにね」
It's too bad because ... で「せっかく…なのにね」
ーIt's kind of a shame because their designs are so cute.
「せっかくデザインが可愛いのにね」
It's kind of a shame because ... でも「せっかく…なのにね」を表現できます。
ご参考まで！
カナダ 
