The point remains - they're adding a bunch of features for free and most users will benefit from them. I'm far more interested in account unification and improvements to the phone app than 3D maps. Your inference that the update is a dud for older devices doesn't ring true.
Sorry, I should've said "What's your point?" instead of "What's the point (in the update)", the first question is what I meant.
I don't see the OPs point as 3GSs getting the update aren't better off than Android devices on 2.3 which still have access to many backported Android APIs.
Some features are missing from the compatibility library, but have been made up by open source projects such as ActionBar Sherlock (which is great by the way if anyone hasn't tried it out yet).
I also happen to develop for Android, and yes, the ACL does help, but it's still a PITA to develop an app which will look the same on all devices. You will have to use ActionBar Sherlock (or use custom layouts if you want special features in there), style every single control, and test, test, test. Apple's decision to include the 3GS is IMHO a VERY clever one, enabling app developers to very soon use iOS6 as min target. iOS6 might hit 75% marketshare within weeks after release (only leaving out a few iPad 1s which can't upgrade from iOS5), leaving devs only with iOS 5 and 6 to support - and it's very doable to include 6's features and fall back to 5er APIs if necessary. On Android you would need to support 2.2, 2.3, 3.x, and 4.x to reach a similar user base percentage (http://developer.android.com/resources/dashboard/platform-ve...). Also, it does not pay off yet to use 4.x features, that's only 7% currently. All those 3000+ different cheap Android devices with API version <= 2.3 are an obstacle for app innovation.