Key/Icon to cycle through targets

It would be extremely helpful if a key (like TAB) on the keyboard would cycle through all your in-range targets. The first click would switch targets to the closest enemy, the second click would switch to the next closest, etc. This is certainly not unprecedented, it is a popular piece of functionality that many other MMOs include.

And for mobile devices, there would be a setting in options you could tick to show a 'cycle targets' icon in the display, similar to how the emote icon can be displayed or hidden. When displayed, tapping that icon would cycle through your in-range targets in the same manner. And if you do not want the extra icon on your display, then simply do not tick the box to show the icon.