I think Steve Krug of /Don’t Make Me Think/ fame answered this question for me: it doesn’t matter how much is on the main page, so long as users can find what they are looking for quickly. I believe he even cites some usability testing he did where they saw that users only really scan and thus only really see the thing they are looking for.
Usability has to be the king here. If users can’t access the information we’re trying to provide – no matter the desnsity of the offered data – then it’s like the data is not even there.