Am I the only person on the planet who vastly prefers the newer design?

Yes, the larger images were nice to look at - but they got in the way of actually viewing the content for me.

My personal viewing habits of the newsfeed are to give facebook a glance over once a day with my morning coffee. The purpose is to get an overview - quickly. The newer look got in the way of that, especially when viewing in smaller windows.

There are also all the folk who aren't looking at it on large displays, and maybe consistency of experience is important too.

Sure - maybe there's a metrics issue too. But I've seen more than my fair share of usability tests where things that my "design" persona like end up being disliked by the people who actually use the site.