The colored singleton buckets are distracting.

A key strength of Omnifocus is a general lack of visual distraction and a facilitation of focus. Up till now the user's eye has been presented with only two information layers: a generally muted background, and a colored foreground for next actions.

The colored buckets introduce a third visual plane (eye-catching points of blue) which does not correspond in any useful way to a third information layer.

The visual contrast between projects and singleton groups should be enough to distinguish them, but no more. To minimize visual noise, I would suggest that the "bucket" should be the same gray as folders, and in the same graphic idiom (simple and unelaborated) as the regular projects.