Most of the people that complain on eBay simply don't like store windows. They don't care if it helps your sales or not. They don't like anything extra, no images, templates, sounds, nothing.
If you look at eBays biggest sellers you'll see they all use extensive templates, images, galleries, and anything they can to draw extra traffic. Because it works. In general their templates and images are much larger than the size of our store window. Yet they are eBays biggest sellers.
Our Store Window feature uses 28k of images and would take about 6 seconds for a dialup user. Happening mostly in the background while the buyer views the text and other imgaes in the listing.
Have you had heard any of your buyers complain? Or is it only these other eBay sellers complaining?
In the end do what helps you get the most sales for the highest price. Listen to other peoples feedback but make sure to take your own business and experience into the highest consideration.