By this time it's too late for any chance of an early end to the war. Even if you have the most optimistic scenario for Valkyrie there are simply too many people who have been affected by Nazi propaganda that the German race will be extinguished and far too many people associated with the regime's crimes for it to be anything other than a fight to the death.
This would likely butterfly away Valkyrie, as the resulting purges would likely kill off the German Resistance or force them to keep their heads down and out of trouble for the foreseeable future.
However, this might put the Allies on the Rhine much earlier than OTL. If enough German troops defect with Rommel, that's potentially another army the Western Allies have at their disposal a la Fox on the Front. That could end the war early and possibly put the dividing lines further east.
Rommel would have to finesse his defection very carefully--OTL he committed suicide (being a Catholic, this is a VERY big deal) to ensure his family and staff wouldn't be murdered, so he wouldn't want to put them at risk.
If he started bringing relatives into France and Belgium, that would look really strange and might tip off the Gestapo that something's up.