Looks a lot better than when I last checked your link a few days back.
IMO you are trying to render too many complex geoms at once. I would strongly consider:
- Creating tile packages for the 2012 Presidential Election Results and USA Black Population layers in ArcGIS Desktop.
- Publish these to AGO.
- Simplify the same layers significantly and use integrate tool in ArcGIS Desktop to clean any gaps.
- Publish as a hosted feature service
- Use this hosted feature service as the popup for the tile services
This should be lightning fast.
In short the rendering is taking awhile as you are pulling a large # of geoms from the service. The alternative is to play with your layer scale level ranges to perhaps switch between state/county/tract to load less geoms for each scale level.