From what I understand the roms are being built by google and not samsung. So I am almost certain there will be a ton of watch faces and styler apps that will be created for all android wear devices. As much as I like my Samsung gear watch there are very limited faces and the styler app for it drains the battery super fast. I hope this wont be the case for android wear.
watchface API is now rolled out iirc, there's even a couple watchface apps in the market (or so it claims, haven't tested it out). Just found this one too: BCD Clock for Android Wear. I would suggest this google+ group for details, is where I found the above app.
I plan to make it
For now, I have this app (released today) with 20 faces. You control it from your phone.
But soon, I will make something that allows you to choose step by steps the backgroud, font,...
https://play.google.com/store/apps/details?id=com.vuxia.wearFaceCollection