The switch has absolutely nothing to do with the stopping ability of the brakes. If you had a switch replacement and the braking efficiency diminished, it's because the brake system has air in it after the replacement. It has nothing to do with the switch itself.

Now to the OPs problem...
650 miles should be enough to have "mated" the pads to the rotors so I don't think it's a wear-in issue, but it is possible depending on how much usage the brakes have seen so far, but there's many other potential causes. Some causes have been mentioned already, i.e., mechanical problem with the lever, or the caliper, contaminated pads/rotors. Not mentioned yet but possible is a hydraulic issue with the master cylinder or caliper. Finally, and this is probably the most unlikely but still possible, and the hardest to diagnose, there may be an issue with the ABS Module restricting flow/pressure through the module to the caliper.

If the OP wants to work this out himself I'd be started with the simple stuff. Eliminate the potential causes one at a time until you find the problem. If you want the dealer to find and fix the problem, good luck. Some techs/dealer service depts. are better than others.

Obviously it's a new bike, therefore a warranty issue, so I'd expect the dealer to take care of it.

 

so what happens if during the next week or 2 you can't stop and hit something ?

what i am getting at is if you think the brakes are not working correctly- get it fixed.
the consequences are too serious not to take care of this

Mike