If I'm not mistaken, this measure was implemented to lessen the strain on the server. I know it's a bit of a mild inconvenience, but it's been lessened from a more annoying 30 seconds and it's not like 15 second will hold you up by that much. Just make certain to double check that your search terms are spelled correctly and avoid refreshing the page during the middle of the search.
Edit: Oh yikes, double ninja'd