Thank you. All 2D surfaces can/are accelearated I would bet money that the lag is in legacy apps. For some reason, new apps have to opt-in to hardware acceleration. I can't see any lag at all in all of the hands on videos I'm seeing.
By opt in, they have to bump their targetSdkVersion, so it's not a big deal. Source: http://developer.android.com
Yes, it seems that although hardware acceleration was possible prior to Android 3, it wasn't as easy as it is now. It also requires a degree of care to be taken by the dev to do well.
Given that it hasn't been available in phones until now (that is, in ICS), it’s understandable why we've seen laggy UI.
By opt in, they have to bump their targetSdkVersion, so it's not a big deal. Source: http://developer.android.com