Having the feature, that when you mouseover an ability or skill, it will create an outline around you with the range that particular spell will reach.
For example, Cure III has 6 yalm range, it will show a small 6y outline around you. Medica II 20 yalm? Medica 15 y? same mechanic
Also, add an ability where mouseover a party member's icon will show you if they are in range of a particular heal or not. For example, say party member 3 is 50 yalm away, you can put your mouse over his name and without clicking, be able to see if he is in range of a Cure/Physik, etc... Also, it would show if people are in range of AOE heals using the same mechanic. Many times its very difficult to tell if someone will be in range of an AOE heal, especially when casting in a rush. This allows healers to more easily choose heals/abilities to use and position themselves.
Finally, increase the range of Whispering Dawn to at least 25y, right now it seems to always miss a few people.