What can’t you live without in your Traktor mapping?
For me I always map the setting on my key knob super fine to match keys by ear.
As well, a knob mapped to loop size (preferably an encoder with detents).
Play 
Deadmau5’d
I’ve come to stop mapping stuff since that usually means shift layers which I hate with my life. So each day I map less and less with each new controller I add to my setup lol.
Sync for sure.
Ha. Seriously though, a knob for loop size, and hot cue on/off/delete buttons.
Yea we all couldn’t live without some basic transport controls but I love traktor mapping tricks.
I typically accomplish that ^ with Beatmasher. That’s cool though!
Shift!
7 modifiers 
Loading n browsing controls (BCD2000 jogs and 4 buttons across the bottom).
Focus on and clear the search box (macro) so I can just start typing in what I’m looking for.
Absolute, relative and internal mode switches for each deck (with LEDs so I know at a glance what’s what).
Cruise … essential for when I play long 7-8 hour sets and have to go for a piss… and I think there is a que at the bogs.
play button
LED feedback.
I always map buttons to manually switch master tempo to whatever track I need. I use my master tempo for effects instead of syncing, and I usually have it set to auto, but sometimes if I’m switching tempo I like to use effects at the speed of the incoming track.
The buttons on my maschine to skip forward and back 32 beats seamlessly. Can skip through songs without anyone knowing .
Very useful feature, I use it as well when I want to skip some shite vocals or kinda remix it on fly!