Why is everyone trying to add such complicated things to lilies. Really all you need to do is swap the way that lilies work around. As they are at the moment they promote bad gameplay. Building them off medica and medica II only promotes using those skills too often, and regen usage is limited because of its duration. Instead the lilies should encourage the player to follow correct whm gameplay.

WHM healing priority is: off global skills -> regen -> cures
You should use tetra, asylum, assize and benefic to heal first since they are free, so these should be the skills that build lilies.
Cure/Cure II or other gcd heals should be the skills that benefit from lilies. You use them after you have exhausted your other options and you should get a bonus from doing things in the right order.

I'm in favour of them being deleted completely, but if they are going to exist they should at least promote the basic gameplay of the job.