I don't think that was it. Slashdot would only run stories from their 'content partners' like ZDNet and the Register, so they were always 2 days behind Reddit/HN/Twitter/etc.

(When RMS was 'cancelled', that would have been a huge deal there in the old days, they had one post days later.)

Also Digg wasn't just a graphical redesign, they changed how the site worked. I don't think Slashdot ever did that.