Again, feel free to bump up the text size if it doesn't work for you. The site is designed to adjust its layout based on the font size, so the line length will never change. One of the best features of the web is it gives users the ability to adjust these types of things based on their own personal needs.
All of that said, I do intend to redesign the site with a larger font size. But, in the meantime, a little CMD (or CRTL) + + will go a long way ;)
Yes #333333 and 0.875em thin text looks cool on a grey background, but it is hard to read even with these young eyes.