Agree with all your points. I'm surprised Apple haven't put more thought into the features of the iTMS. Online shopping site conventions lead us to expect certain features (power search, wishlists, etc) and that they work in similar ways.
Regarding wishlists, however, you can do this locally by simply creating a playlist for your wishlist items within iTunes. This method works well enough but it limits the ability to share your wishlist with anyone beyond those on your network that you share your iTunes library with. I guess you could submit it as a suitably titled mix, but that's a rather clumsy solution the problem. Conventional wishlist functionality would be a far better solution.
6 Things I Would Change in the iTunes Store