I love the new addtion allowing us to subtarget directly from the action bar. Its helpful to those of us who do not want to or know how to macro everything. It also keeps you from having to exit target lock "B button" exit target "B Button" select new target "A button" select cure "over a few times" confirm "A Button" just to heal your buddy in a duo party.
The select cure and use subtarget is awesome here.
However when i select "thunder" I am now bothered with the subtarget ever time also. I would suggest that if we are fighting a target there is no reason to subtarget attacks. If we wish to change target of attacks you can make us exit target lock and select a new target or add a all or non attack spells only option to the target mode selection.

Otherwise keep the nice addtions coming ^^