Looks like LW 2.0 is using a 20px font size, and 25px line height, which is in range of what is recommended.
Correction: the body text has font size 19px, line height 32px (ratio of ~168%). This is definitely too widely spaced.
Yeah, this was a bug I accidentally seem to have introduced a bit ago. I apologize. The correct ratio I wanted to use was the one that Tufte CSS uses, which is 21px size to 30px height, which is a much more reasonable ratio. (This will be fixed in the next few days)
What are your first impressions of the public beta?