Yes, it’s too thin, and ended up breaking the keyboard on the full size iPads when they brought that thumb rejection over in iOS 6.01
My typing has been significantly slowed down since then, and I am constantly having to make corrections as it skips over lots of characters I type when it thinks I’ve just rested my hand on the device.
Prior to iOS 6.01 I was able to type at speeds not much slower than a physical keyboard. Now it feels like my typing speed has halved to below 50WPM. It has me considering iPad alternatives for the first time, it’s that bad.