https://dcurt.is/facebooks-predicament
Essentially this big, beautiful design driven redesign ultimately never shipped because users spent less time on it. Certain design 'improvements' like increased padding between stories reduces density and as a result tends to reduce readership, for example. The internet as perceived by Engineers and Designers is quite different from the masses (even with Reddit's demographic differences from FB taken into account).
Reddit needs to be really careful with a redesign: data should lead the rollout efforts, not design. I think they are due for some UX improvements, perhaps around a gradual UI refresh; however, I have little faith in the product leadership at Reddit to pull this off. Huffman and crew need to be willing to can the entire redesign if user research and data come back negative.