You can signup your email here if you want to receive notification of when the new developer guidelines are out, but so far all I've heard is crickets.
The actual Kindle Fire tablet received a pretty lukewarm review from the folks at Wired, most notably that it had a very clunky web browser:
The Fire’s processor, a 1GHz dual-core chip, appears all but insufficient for fluid, silky-smooth web browsing, an area where I found performance to be preternaturally slow.Technically speaking, eBooks are basically big long websites built with the same type of code. Therefore, it does not bode well that the Kindle Fire can't render simple websites, let alone a complex eBook.
Hopefully, Amazon is not suffering from oligopoly syndrome, where a small number of large companies have massive market share thereby squashing the economic forces that compel companies to innovate and devote themselves to customer satisfaction. If you want an example of oligopolies run amok, just look to my home state of Michigan. Most of the auto assembly plants were shut down years ago followed by the taxpayers having to bail out two of the Big Three. I hope that Amazon can stay on their toes in the fast-changing world of ePublishing, because a lot has changed just in the last six months and readers are clamoring for better eBooks.