Well, game/story-wise I think facing a target to heal makes sense. Our healers aren't all-powerful in knowing where everyone is all the time. It is not like your character has their back to the party and throws out a heal bouquet and hopes the right person catches it. So facing a target for a heal seems logical in the fact that your character is acknowledging the location of who they are healing. Mechanics-wise, I see how this can be annoying for non-legacy users.

As far as legacy mode, I have helped a few people in using it and the common problem I found they had was actually their movement keybinds. Forward, Back, and strafe can stay the same in both legacy and character based movement. However, the turning needs to be changed. In legacy, you need to change your left and right character turns to left and right camera turns. Perhaps that is causing your dizziness or maybe your camera turn speed. (I'm just guessing since you stated you had no problem with legacy in FFXI). If you haven't tried those see if that helps. I know it isn't the solution you want, but perhaps it can help.