I'd like to see a more striking indication when multiple photos are being targeted by develop adjustments, vs. single photo. Its just too easy to leave auto-sync on inadvertently. As it stands, one has to keep peering down at the (auto)sync button to be sure...
Also, along with this, I'd suggest handling the auto-sync button in a manner consistent with all the other buttons. i.e. button label indicates what will happen when you click it.