While Android O so far seems to contain a number of 'under the hood' improvements, there is one which is clearly designed with end user interaction in mind. This particular improvement revolves around the use of shortcuts on the lockscreen. In short, on Android O, you can actually customize the lockscreen shortcuts to your particular liking.
Typically speaking, those running stock Android will be used to not having the option of lockscreen customization afforded to them. Instead, the right shortcut is resigned to the camera shortcut and the left shortcut dedicated to the 'mic' shortcut. This of course, will be different for those who run a flavored version of Android. With the latest developer preview of Android O installed, the options are a lot more varied and the key is buried within the System UI Tuner. Once here, you have the option of setting the shortcut to a number of different quick access points for each shortcut (left and right). At the moment, the list on offer is pretty standardized so you should expect to be able to set either shortcut to Chrome, Wi-Fi, Data, battery, the Play Store, and so on.
Of course, if you are not that interested in dedicated shortcuts on your lockscreen, then this will not really be for you. Especially if you are much more inclined to quick launch the camera or the voice assistant in the first place. Although in either case, it still is good to have the choice and that is exactly what Android O seems to be bringing to the table. Keep in mind that the System UI Tuner does not come activated at install. You do need to bring down the notification shade and then hold on to the settings 'cog' for a few seconds to manually activate the System UI Tuner availability. It is equally worth keeping in mind that as this is a developer preview, there is no guarantee that this will make it into the final release of Android O when it is made widely available. In the meantime though, if you do have a compatible device and would like to test out Android O and its customized shortcuts, you can now download the factory images and flash them to your device.