I have to say I'm surprised. I've gone through many of these sites myself and found them cluttered, unclear, hard to find things on, and lacking in any meaningful content.
I do this type of work for a living, and you're right. It is important to make the site easy to navigate and read. It's good to make things simple to find. The writing should be short and to the point.
That does not mean we need to reduce arguments on important national issues to a first-grade level. As a voter, I find that offensive. Clear communications would help many of these sites. Less cluttered navigation and design would be a mercy on many. But I appreciate any site that gives readers credit for having two brain cells to rub together.

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The glaring omission.... and the rest.
Ron Paul 6.63
Seriously, what possible reason could there be not to include Ron Paul in an article about campaign web sites? Don't you guys read your own charts?
Here's the rest, for those of us who follow the whole story:
Kucinich 1.39
Gravel 3.82
Dodd 4.56
Brownback 5.24
Hunter 6.88
Keyes 7.89
Biden 8.20
Tancredo 8.40
Looks like Dennis Kucinich takes the crown for simplicity by a mile.