Pretty sure we'll only see dual channel on AM4, for cost and complexity reasons.
Sad thing is, you can guarantee there will be lots of people who will see that as a negative, despite having zero use for >2 channels.
I mean, how many people went for X58 and bought a 3x2GB kit back in the day lol. I used to get so many people ask me why I only had two RAM sticks in my X79 board whenever I posted an internal system pic haha.