I don't think any smartwatch in this or next generation will be officially designed for self-sufficiency. The current focus is notification and senor feedback to the phone.
The Gear 2 like the Gear 1 will require a handler by the smartphone for most of the analysis of the sensor data.
That's where the advantage of the Gear 1's Android OS comes in.
You can make it self-sufficient by installing any Android App directly on it.
With the null rom, you should be able to connect other accessories to it as long as you have an app that supports reading the sensor data.
Please Thanks if it helped!