In traktor you can set the grid points where the time signatures vary. For anything 3/4, you can quickly loop that third bar to make 4 bars per measure for mixing. It's an old trick from turntablism to create more danceable breaks out of jazz beats. Think about squarepusher tunes as well. It would be kind of kool to see a time signature tab in traktor or any dj software with it being labeled automatically during analyzing.