This is a long standing annoyance I've had with Illustrator and its print-based, white paper logic.
How the heck can you tell what a layer contains if the object(s) in it is white? With Photoshop, you see the transparency grid in the Layers palette. But Illustrator's Transparency grid doesn't show up in the Layers.
Besides coloring things light gray, are there any tips to seeing white objects in the Layer palette?
Perhaps just name the layer "White Objects that I can't see in the Layers Thumbnails". You know it is easier to name layers now, so this must be the intended end user solution from Adobe to your issue.