One thing I was not too thrilled about is the flat mount brake interface. It only allows a 160mm rotor front and back and cannot be adapted for a larger rotor.
I used to use a 203mm rotor on my LHT back in the day and now use a 180mm. Still it's not allowed by the manufacturer so you could say that nothing has really changed as the maximum allowed rotor size has always been 160mm.
Also one thing that makes me not worry about the 160mm front rotor is the fact that if I get the new disc trucker I actually have two rotors I can use. My LHT has a rear rim brake I simply do not use all that much because it sucks. So all the heat I've been generating has been been going to one rotor only and that's not optimal.
Also I know from personal experience that you can heat up a mechanical disc rotor to between 300 and 400 degrees celsius without loss of braking power or brake fade. I haven't managed it myself but my wife who occasionally has bad bad braking technique properly blued her rotors in the alps.