Paper Prototype Question

Our project is all about allowing customization of the ITunes music store and part of that includes cleaning up the page layout.  Getting rid of unwanted catagories, rearranging content boxes, etc.  As I was helping make the paper prototypes, I couldn’t help but think “Will this page look less cluttered and easier to use?”  When I looked over the entire ITunes store home page, I noticed not only all the content catagories but also the huge amount of ads.  Bright, colorful, and sometimes animated ads.  The paper prototype ads merely are labeled “Ad” but that really doesn’t accurately represent the page.  It’s one thing to see something that’s already identified itself as an ad with just a boring text label but it’s completely different when it’s purposely trying to get your attention.  Yes the user will be able to narrow down the catagories displayed on the page to what they want yet the ads are still going to be flashing at them, trying to distract the user.  There are obviously limits on how accurate of an analysis paper prototypes can provide and I just wonder how much of a difference in ease of use there’d be in real practice.