I wouldn't be opposed to a dual targeting system so long as they could make it easy enough to control which target you're trying to set or change, though I could see that potentially adding as much complexity as it's saving.

What we have now already does have quite a bit of flexibility. For healing, so long as in party based content I stick with "Enemies" mode filtering, so that up/down cycles the party and left/right cycles enemies, I haven't had much trouble targeting who I want. (There's also L1+ up/down when you need to be more specific about which enemy to hit, though that's usually more of an issue when playing DPS or tank than for healers.) The only time I have trouble targeting is if I accidentally switch targeting filters, which only happens if it's hectic enough that I get a bit fumble-fingered, and only rarely even then.

I do agree that the soft targeting is of limited use on healer, who might want to cast several healing skills in a row or several attack skills in a row depending on how the fight is going. It's more useful for a damage dealer's support skills, which are more likely to be one-offs.