On the one hand, I totally would love to use these because my kitties seem to go through cycles where I get all girls or all boys. I think it's also make for some interesting kitty backstories
However, I really am not sure it would work out so great in reality. If I could take my two most awesomely traited kittens (both boys) and change one instantly, that means more time with a perfect pair to get more awesome offspring. On the surface, that sounds great, but I think it would remove a lot of the fun challenges that come with breeding. You'd have twice the chance of having the exact pair you want to breed and that seems more boring to me.
If this were to happen, I'd think it should be one-time and relatively expensive, like a surgery - a big deal. But (sorry guys) I would actually miss some of the frustrations (please be a girl, please be a girl) that can lead to awesome unexpected pairings because there isn't a more
appropriate mate.