The new target marker system is interesting, but I think using the scroll wheel to apply markers is too cumbersome for the feature to actually be useful in a lot of situations.
For me the ideal functionality would be if a specific marker could be set to be automatically added to a target whenever the group leader tab targets that target. That way whenever the leader tab targets something the whole group can see what the preferred target is and focus it.
I know it's currently possible to accomplish something similar using the marker wheel, but I have not had much luck actually using the wheel to tab things in the heat of battle. I find the basic one-click tab target system much easier to use.
Are there currently any addons that can auto-apply a marker when you tab target something? Is there something that would be possible to create given the currently available APIs?
Edit: I've just noticed that you can actually keybind the target markers to individual keys, but you can't set a target marker and tab target to the same key. I still think it would be really handy if there was a way to do both with one key press.
The target markers can only be applied if you move the mouse manually above a target and it only can remove this same marker if you move the mouse above that target again.
If no target below your cursor -> marker will be set to yourself! (or if same marker was set to an enemy already it might remove it on first applying without showing it at yourself)
Addons cannot circumvent this and there does not exist any good API to fullfill your request.
It was created to help visibly impaired players so that their group leader automatically sets the target markers on the enemies and the visibly imparied players get the target markers at the compass, and if they turn around the screen reader detects that and reads it to them so they can find the enemies easier.
Mayeb this can help you too, to auto set markers on enemies in fight -> only the group leader can set the markers and he obviousl needs to run the addon then