Motorola's contribution to the Nexus - and to Android 5.0 Lollipop in general - also includes Ambient notification mode. When a new notification arrives, the lockscreen will light up in a power-efficient (on AMOLED) black and white mode.
Notifications in the new version of Android are visible on the lockscreen. You can hide notifications from certain apps for privacy reasons (or just to mute an annoying app). You can mark other apps as "priority" and then use the built-in filter to hide unimportant events from the lockscreen. The wave-to-wake gesture from the Moto X (2014) is missing though.
Lollipop also supports always-on voice commands, implemented either with dedicated hardware or with the chipsets' own utilities. Qualcomm added such functionality as far back as Snapdragon 800.
It's not an 800 though, the Nexus 6 is powered by Qualcomm's latest Snapdragon 805 chipset, which brings the latest CPU and GPU design. We'll have to wait and see how it compares to the Tegra K1 in the Nexus 9 and the Apple A8 in the iPhone 6 Plus.
It's important to note that Qualcomm still doesn't have a high-end 64-bit chipset on the market and full 64-bit support is one of the biggest changes in Android 5.0.
Google's move to higher price points for both the Nexus smartphone and tablet drew some criticism but Android's wide stance could never be covered by just one phone and one tablet. Android One devices took stewardship of the entry-level, which leaves the Nexus line to focus on the high-end.
This sends a clear message to Apple - Android devices can compete on experience too, not just bang for the buck. Android vendors have been beating that drum for years now, but with the Nexus 6 this is the official party line.
It puts Android vendors themselves on notice - the price tag will prevent the Nexus from cannibalizing phablet sales, but it's a benchmark against which all other phablets will be measured.