Interesting thoughts Utah,
A couple of things i'd like to point out - FWIW I've been in the Flash/RIA game for over 10 years so like to think that I know a little about the topic at hand

First-up i'd have to say that usability and SEO are really 2 x separate topics and IMHO can't be directly compared.

Flash and SEO - can most definitely be compared! FWIW Flash has allowed the inclusion of metaData into Flash Player 8 SWF files since it was released in 2005. If Flash designers/developers haven't been leveraging this feature (for the purpose of SEO) then thats not really the fault of Flash. Additionally, Adobe's new Search Engine SDK further enhances the indexability of SWF files - This great article by Jeff Muendel at CNet goes into some good detail about the new SDK and discusses how its really up to designers and SEO developers to leverage this.

On the topic of Usability and User Experience (UX) they are not 2 x separate entities existing in isolation.  Quite the opposite, they are intrinsically,  linked/related. If you take a quick look over at UXMatters you'll see this theory confirmed - they have a great definition of UX which goes something like this; "UX - Encompasses all aspects of a digital product that users experience directly—and perceive, learn, and use—including its form, behavior, and content. Learnability, usability, usefulness, and aesthetic appeal are key factors in users' experience of a product."

HTH
Matt Voerman - Adobe

Great insight. Thanks Matt.

I agree with Matt.  You really can't compare them. Unless your brand is so big and you are an authority site, you must focus on both usability and seo.

you can have the most functional and user friendly site in the world, but it wont mean much if no one can find your website.  Once they are on your site, it must be appealing, have great content, and be user friendly.