The "feature" doesn't exist. The blue/white wire on the WR has the same function as on the YZ450, that is, to retard the timing in neutral. It does NOT "provide a couple of dead strokes".
The way it works is that there is a contact in the neutral switch that grounds the blue/white lead when the trans is in neutral. The CDI responds by retarding the timing a few degrees to lower the idle speed and make the engine less likely to kick back at the rider while starting (speaking from experience, that's a serious concern). Since the lead is grounded only in neutral, all one need do to "disconnect" it is to put the bike in gear, any gear. The lead is then open, and the ignition map
returns to normal.
This bit of mythology went around the 426 world for a while. People decided that the blue/white lead weakened the spark (although no one ever provided any logical cause for deliberately doing that) and that disconnecting it made the bike start better. The fact in both the 426 and the WR cases is that some bikes with different jetting setups will start better with more advance than with less. Jetted right, they should start more reliably and with less effort in neutral.
WR Dave is correct in saying that the kick starter spins the engine faster, and as to combining the use of the two devices, there is no hazard whatsoever in doing so, or even in bump starting it while doing both.
All 3 of my 450's start so much easier in neutral than in gear (with the blue/white effectively disconnected) that the real "cheat" for me would be to put a button on the handle bar that I could use to ground the wire while in gear, not the other way around. All you need to know is whether your bike starts better in gear or out. If you're starting it in gear now, then disconnecting the blue/white will have the same effect as Dumbo's black feather.
Incidentally, the starter drive in the WR is equipped with a torque limiting device intended to protect it from damage if the the engine kicks back. There is no such device on the kick starter to protect your foot.