This update will of course cover some regular bug fixes but it should also add some new features to the Apple Watch. Apple will likely add the ability to track your Apple Watch in a similar way to Find My iPhone. Rumours also suggest that there will be some new health features such as sleep tracking though this feature may be slightly further off.
Apple may also be working on some third party features within the watch faces enabling developers to add small widgets to your watch face. Reports say that Apple are working with Twitter on a widget that will be placed on the watch face to give you quick updates from your Twitter account.
These third party features should be very useful and it will be interesting to see exactly how they work. Hopefully at some point in the future Apple will decide to allow third-party watch faces on the Apple Watch though I wouldn’t expect to see that too soon.