1. As a PS4 player, my 32 crossbar slots are too precious to use one on a command like this when I can get equal or better results through attack macros.
2. This is functionally no better than doing attack macros with <t> and <tt>. What happens if your tank is rotating targets? You can't reliably place all 3 dots and bane on the same guy with assist. That is why I have <f> built into my attack macros.
The idea of the faerie having her own target is intriguing, but probably too unpredictable to work with as she will switch whenever she auto-heals someone.
I agree with you 100% that faerie self-heals should be avoided and that using <t> and <tt> on healing macros is a horrible idea. That is why I don't use <tt> on any of my healing macros. Every healing ability I have is set up to target on my main target so there is never any confusion or errors. I have t, f, and tt on my attacks so I can use those without switching off the tank.