Developing a small, arduino-like IoT product for monitoring and tracking

Hey guys!

Long story short, we're currently developing this small, water resistant IoT product which can be used for monitoring and tracking different things. The HW would be top-quality and the SW would let you come up with all kinds of neat uses for it. 

We're now trying to find people with specific knowledge and interest to find out what (if anything) they would want to be able to do with a product like this. What sensors and other features do you find most important? 

The proposed specs at the moment are:

Sensors:

3D Accelerometer
A-GPS Location
Temperature
Humidity
Pressure
Gyroscope
Magnetometer
Ambient Light Sensor

Connectivity

2G Quadband GPRS
WLAN
BT 4.1
Micro USB 2.0
GPIO pins on PCB
JTAG on PCB

We'd really appreciate any feedback and opinions you can give. We're trying to make the final thing as awesome as possible, and we'd be stoked if you could be a part of it!

I don’t know about sensors, but,

I would suggest you have some of the following available: SPI, i2c, serial. That way, if the hacker that buys your product wants to sense something you didn’t include, they are readily able to do so. I also don’t know if an SD card makes sense. I suppose power outages might be one reason, or, maybe a remote sensor that sends data when a proper AP is in range. Don’t forget a few slave select pins, if you add SPI as a connection method.