Google's Android 2.2 wasn't meant to be used on tablets.
Recently Hugo Barra, director of products for mobile at Google, said that the current build of Android--v2.2 aka 'Froyo'--isn't optimized to be used on tablets. Barra even went on to say that the Samsung Galaxy Tab--which uses Android 2.2--isn't really a tablet, but more like a big phone.
"Android is an open platform," Barra said in a short interview. "We saw at IFA 2010 all sorts of devices running Android, so it already running on tablets. But the way Android Market works is it's not going to be available on tablets that don't allow devices and applications to run correctly. Which devices do, and which don't will be unit specific, but Froyo is not optimized for use on tablets."
Barra added that if tablet manufacturers wanted Android market on the Froyo platform, the apps just wouldn't run, as it's not designed for that form factor. "We want to make sure that we're going to create an application distribution mechanism for the Android market, to ensure our users have right experience."
It's reported that Google wants to evoke the "wow factor" in tablets, adding custom animations and user interfaces. Although Gingerbread and Honeycomb are rumored to be tablet-friendly, there's speculation that Google is working on an exclusive OS to be used on tablets--most likely a modified version of Google's Chrome OS.