Google says the update includes "important features that improve merchandising of applications, streamline the browse-to-purchase experience, and make it easier for developers to distribute their applications. A lot of the makeover is visual. For example, a new carousel on the home and category screens will allow users to quickly flip through to view promoted applications.
Additionally, new categories for widgets and live wallpapers will be added. More unspecified categories will be added, too, and the app details page will now include related content, so users can find similar apps easily. All the information about an application will now be accessible on one page; no more tapping different tabs.
In the non-visual area of change, developers will be able to target apps by screen sizes and densities, and also by GL texture compression formats. Google is also increasing the maximum .apk size to 50MB.
One large change that developers will applaud and that users will not is the Android Market's refund window. Currently 24 hours, it's going to be cut to 15 minutes. Google says this is "since most users who request a refund do so within minutes of purchase," and to help developers with accounting.
However, it was this 24-hour window that was the best part of the Android Market. 15 minutes is simply too short a time to truly experiment with a "deep" app, such as Seal or Locale. We'd add, however, that 15 minutes is plenty for a simple game. One idea that's been tossed around for a while is to allow developers the ability to specify refund times, or no refund at all.
This change is going to make folks a little leery of expensive apps. Locale, for example, is $9.99.
Finally, Google is still missing either a Web or app interface for the Android Market. One can always hop over to AppBrain to check out apps in a Web interface, but you can't buy there. Google's Andy Rubin showed off a web interface at Google I/O in May; since Google says more changes are coming, we can hope that is one of them.