If the weather overlay was something that could be toggled on the sectional view, we could use it with discretion in the congested yellow areas. I've used xm weather overlays on a similar product in sectional views, and never felt like the blending was an issue.
Nonetheless, this would not be an issue in vector mode. I prefer to have my moving map display configured on the ground before takeoff so I don't have to keep adjusting it in flight. Without the weather overlay in navigation modes, I tend to toggle back and forth for in-flight updates, as well as pulling up current metar information as I approach my destination. It requires more attention from me than I would prefer.
Thanks!
Don