I saw a poll on ESPN's front page about this yesterday. The choices were 15, 12, 10, and 7. In our instant gratification society, 10 minutes won with 7 minutes being a close second.
I think it should be lowered, but only to 12 minutes. With just that small decrease, it would shorten the first round by about 1:15-1:30. That is plenty, people need to calm their ADD.