Right now as it stands, I don't think there is a need to "fix" anything until players actually start using it. The perspective of English-language people who were on the Media tour didn't help.

Look at Red Mage and look at Scholar, and now look at WHM. It makes perfect sense what they are trying to do here, reduce the core skill complexity down to just 2-3 skills you are supposed to be using as your core skills, and the other heal skills layer on top. More lilys, the more you can cast. Your core skills are healing, not DPS.

The problem here, compared to SCH, is that people are looking at this mechanic as a required thing that will be available at all levels, when that does not appear to be the case at all.

So the lily system should not be rewarding DPS at all. At best it should reduce the cast/CD time of other healing spells, but there in lies the problem. The people complaining are not playing WHM like Yoshi-P thinks they should be playing, and being "forced" to play this way to take advantage of the lily system in their mind encourage overhealing when the reality is that if you are playing the way Yoshi-P thinks you should be playing, you would not be overhealing at all if you actually pay attention to the HP gauges.

So where could it be improved in theory without yet playing SB?

Get rid of RNGesus gameplay. Don't reward overhealing.

The process to getting a lily should be based on casting Cure I/II without overhealing. If you cast Cure I or Cure II and it doesn't overheal, Full lily. If you overheal by more than 25%, No lily. If you heal while having enmity or enmity turns red, no lily. If you cast Cure I without overhealing, you get a free Cure II, and if you cast it without overhealing, free next AOE spell (Medica, Media II, Cure III, Holy, etc.) The Lily system meanwhile should only reduce the GCD of healing spells, and maintained as long as healing spells are used. This would of course require changing the costs of the spells to encourage Cure I+Cure II+Anything.

But all the griping about the lily system seems to ignore the confession system too. There is no way to tell how this will work since none of the media tour people did dungeons, let alone as WHM from what I've been able to locate.