While I find the current website layout quite comfortable and utilitarian, I think the very basic look and feel of the site is probably one of the biggest hurdles you have to gaining more mainstream acceptance from your potential reader base.
Put simply, at first glance it's hard to take the site seriously.
In this day and age of HTML5 and CSS3 a site that looks like it's been rendered with lynx doesn't immediately produce feelings of confidence in the value of the sites contents. It's ridiculous I know, but it's a fact of human nature. Having spent the last 10 years trying to convince customers that something that's free can be as good or better then something that costs an arm and a leg, I know exactly how embedded these kinds of assumptions are.
Certainly I felt some trepidation shelling out when I first signed up, not having a clear idea of the kind of value I'd receive for the money made it hard to pitch to my then-boss too.
Having been a subscriber for a while, I get the most value from the daily mailouts, and occasionally visiting the site for more detail on security alerts, so flashing up the website would make no difference to my experience. But in my opinion, if you want more subs, you gotta make it look pretty.