Why do you relate content being under "computers" as being the reason for not updating playcounts? I don't see any connection.
I doubt whether they will move where your content is shown (and I hope they don't because I think it works well as it is), but I'd be surprised if the playcount issue isn't resolved fairly quickly.
Finally, are you aware that you can use the Apple remote on iPad, iPod or iPhone to play media using Airplay and in that case it will update playcounts, as you are actually playing it from iTunes. It doesn't work with video yet, but should do soon.
Because ALL content shared through home sharing doesn't update playcounts. If you play a song from another computer, it does not update playcounts. I think they will need to either change that or put content back to the way it was for playcounts to work. And I'm pretty sure you could still view your content in the my computers home sharing method on the old ATV.
I forgot to mention another gripe I had. With my old ATV sync'd, when I go to my movies, my music, etc, the screen is there and populated with my media. On the new ATV, I go to my computers, I pick my movies and get something about accessing library for 5-10 seconds. Then I click on a different genre, I get to wait another 5-10 seconds. So yea, I think the old method was far superior. My library is large, but not huge. I have about 120 HD movies and 11000 songs/music videos and 500 or 600 tv shows.
I was using the remote app through the iPad and using the ATV as a remote speaker from my main computer and that worked well enough and avoids the lag note mentioned above. But as you said, it doesn't work with video yet. I'm also concerned what impact airplay will have on battery life of the iPad and iPhone if you streamed directly from them.
I guess this is my thing. If I KNEW 4.2 was going to give me all the functionality I had on my old ATV in one way or another (fix the photo screensaver, airplay enables me to play content from my iMac using the iPad remote) I might keep it. But we all know Apple is very hit and miss on what they decide to fix (it took 5 or 6 updates on the iPhone before smart playlists worked properly with limits.) I KNOW how the old ATV works and it does EXACTLY what I want it to do. Do I wish it ran cooler and had the stronger processor? Absolutely. That's why I said if you gave me the old software in the new hardware I'd be sold. I don't care about buying things from my couch and my bluray player has Netflix and Pandora.
The new iPad remote app is hands down the greatest thing to happen to either ATV. It manages to be far superior to the iPhone remote app.