"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Working to Expand Siri's Third-Party App Integration for iWatch
With input methods for the iWatch limited due to the device's size, Siri's voice capabilities may be one of the best tools for Apple to leverage, and that means improving Siri's capabilities.
The report points out how the Siri of today can’t do things like book a car rental or make a hotel reservation, or use a messaging app other than Messages to send a text. The improvements to Siri would potentially enable those types of things, enabling third-party integrations that don’t require one-to-one business arrangement between Apple and the external company. Current integrations like those with OpenTable and Wolfram Alpha do involve those direct deals, which limits the pace at which new third-party powers can be added to Siri.The report also claims that Apple is working on technology to dynamically adjust what content is being shown on a device's display, offering the example of a running app automatically being shown when the user begins jogging. The technology would obviously be useful for a device such as the iWatch with very limited display size and input capabilities.
Apple has been rumored for several years to be working on a smart watch project, with the company reportedly placing a strong focus on biometrics to include health-related data tracking for the iOS ecosystem.