I just got a Canon EOS 6D. When it is connected to a Wi-Fi network and used for remote shooting and transferring files to a smartphone, after barely 5 minutes the camera becomes hot. Is this normal?
No, it is not normal for a Canon 6D to get hot while transferring images via Wi-Fi.
I do this all of the time for 10-15min intervals and have never noticed the camera even warming a bit, while the camera is sitting in my lap. The images themselves are extremely lightweight for the transfer, its not like it is maxing out a Wi-Fi connection in the least.
I would be interested to know if you have Live-View on during this activity or not, as I do not when transferring files(because I'm using my mobile device to download the images and view).