Here are a couple of suggestions for new features that would enhance the product significantly:
1. An option to darken the wallpaper on the Start Screen as is already done for the scrolling program list. Particularly needed for wallpapers with light backgrounds because Windows still labels with white text even when the wallpaper is near white. Perhaps with a slider to set the level of darkening for both (making the two views match).
2. An option to automatically change the lock screen to the current wallpaper, as is currently done with the Start Screen background.
3. The ability to select solid colours for the Start Screen "wallpaper", even if it means kludging it by creating a temporary image on the fly.
Improvements to existing features:
4. Reduce the blur strength for Start Screen wallpaper. Minimum is currently about what 50% should be and anything over about 3-5% is completely unrecognisable as to the content of the picture as it is currently implemented. More sensible range is needed: we currently have about "50%" at 0 and about "100%" at 5% on the slider and the other 95% of the slider is completely useless.