It is possible to overtighten a QR and in doing so- you may stretch the spindle of the QR. In extreme cases it is possible to break the spindle. The QR Does not have to be very tight- especially if you do not take off the lawyer tabs. They may be called lawyer tabs but they are a safety factor in keeping the wheel on the bike.

The QR should be tightened so that when you close the Lever- it will just take enough effort to leave an imprint on your hand. UNLESS you are using disc brakes and then you should be looking at a different wheel mounting system, but that is a different story.