Oh my Apple TV, life could be so good, so perfect but why...
...does my rental movie not show up when I've already syncd it
...do you "stick" for a second or two when playing files, you never used to!
...do you keep re-syncing the entire library for no good reason
...does a sync take sooooooooooo loooooooooong
...do you get soooo hot
...dont you natively support an external drive
Ahh it could be so perfect
And people wonder why Apple ditched having a hard drive and syncing support.
Yes, it means the new Apple TV technically has less "features" but it takes all the hassle out of using it for what it's made to do, which is ultimately playing iTunes content on your TV.
You will never have to worry about your rentals not showing up, because they will stream (relatively) instantly.
You will never see it wait a second or two for playing files, unless your home network sucks (but at least it won't be the Apple TV doing it).
You will never have to worry about syncing anything ever again.
It will never get hot, it will always run cool and quiet (no hard drive noise!)
No external drive support still, but who wants to deal with setting that crap up anyway? If you are into having your own premium home theater center with hard drives and DVD drives and all sorts of madness, then buy a Mac Mini and run Plex on it.
Bottom line is the new Apple TV is intentionally killing features because those features sucked and caused nothing but problems. The new one might cause new issues (if your network setup sucks, or you don't have a computer to stream "local" content from), but at least you'll never get a headache trying to get the stupid thing to sync, and it won't set your entertainment center on fire.