Maybe in theory it was colorful (I've never read the actual design documents), but in practice the complexity of "legacy" multiple-color controls that were 3d and gradiented was switched to extremely simplified, mono-color equivalents which made me wonder if what I'm about to click is a control or just a simple text label.

I've never used Windows Phone as well, so I can't compare to how Metro looked on those devices. I only know what they've done with Metro on Windows on PCs.