Seriously, it’s horrible. Being able to build proper apps would be so great, instead of simple ways to display JSON files with Interface Builder (yes, that’s basically what WatchKit currently is). Especially watch faces, I’d love to be able to build my own (even powered by Sprite Kit, I know the stock ones use it!), I’ve got so many ideas for things to build.

Source: building / breaking things : Making Truly Native Native Apps on Apple Watch