Been DJing for 3 Years now and personally, I wouldn't want to take the time to sequence the mix. It's much more rewarding to put a live mix out when its polished out of the box. And its OK to remember that just like bands do in production, a DJ can 'punch in' if the mix gets out of shape :D and just edit out the bad on a program like Sound Forge. Ain't no shame in multiple takes!