This thread made me look at old screenshot which I found plenty here. The color palette is one thing but there’s more to it than just the color. It somehow feels warm and at home. There is that foggy blurry horizon and somehow produces richer god rays. Probably it’s just clouds we’re missing? It also seems to be rendering blocks farther than the current max settings.
One thing I don’t miss is the intense lag that I couldn’t even walk/run properly let alone build 
. this might have been the outcome of optimizing the game (e.g. less particles, lower level rendering details on farther blocks, no clouds, etc.)